diff --git a/atcoder/abc378/a.rs b/atcoder/abc378/a.rs
new file mode 100644
index 00000000..064f9850
--- /dev/null
+++ b/atcoder/abc378/a.rs
@@ -0,0 +1,46 @@
+use std::collections::*;
+// https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
+macro_rules! input {
+    ($($r:tt)*) => {
+        let stdin = std::io::stdin();
+        let mut bytes = std::io::Read::bytes(std::io::BufReader::new(stdin.lock()));
+        let mut next = move || -> String{
+            bytes.by_ref().map(|r|r.unwrap() as char)
+                .skip_while(|c|c.is_whitespace())
+                .take_while(|c|!c.is_whitespace())
+                .collect()
+        };
+        input_inner!{next, $($r)*}
+    };
+}
+
+macro_rules! input_inner {
+    ($next:expr) => {};
+    ($next:expr,) => {};
+    ($next:expr, $var:ident : $t:tt $($r:tt)*) => {
+        let $var = read_value!($next, $t);
+        input_inner!{$next $($r)*}
+    };
+}
+
+macro_rules! read_value {
+    ($next:expr, [ $t:tt ; $len:expr ]) => {
+        (0..$len).map(|_| read_value!($next, $t)).collect::<Vec<_>>()
+    };
+    ($next:expr, $t:ty) => ($next().parse::<$t>().expect("Parse error"));
+}
+
+fn main() {
+    input! {
+        a: [i32; 4],
+    }
+    let mut hm = HashMap::new();
+    for a in a {
+        *hm.entry(a).or_insert(0) += 1;
+    }
+    let mut ans = 0;
+    for (_, v) in hm {
+        ans += v / 2;
+    }
+    println!("{}", ans);
+}
diff --git a/atcoder/abc378/b.rs b/atcoder/abc378/b.rs
new file mode 100644
index 00000000..ad8e5d5b
--- /dev/null
+++ b/atcoder/abc378/b.rs
@@ -0,0 +1,50 @@
+use std::io::{Write, BufWriter};
+// https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
+macro_rules! input {
+    ($($r:tt)*) => {
+        let stdin = std::io::stdin();
+        let mut bytes = std::io::Read::bytes(std::io::BufReader::new(stdin.lock()));
+        let mut next = move || -> String{
+            bytes.by_ref().map(|r|r.unwrap() as char)
+                .skip_while(|c|c.is_whitespace())
+                .take_while(|c|!c.is_whitespace())
+                .collect()
+        };
+        input_inner!{next, $($r)*}
+    };
+}
+
+macro_rules! input_inner {
+    ($next:expr) => {};
+    ($next:expr,) => {};
+    ($next:expr, $var:ident : $t:tt $($r:tt)*) => {
+        let $var = read_value!($next, $t);
+        input_inner!{$next $($r)*}
+    };
+}
+
+macro_rules! read_value {
+    ($next:expr, ( $($t:tt),* )) => { ($(read_value!($next, $t)),*) };
+    ($next:expr, [ $t:tt ; $len:expr ]) => {
+        (0..$len).map(|_| read_value!($next, $t)).collect::<Vec<_>>()
+    };
+    ($next:expr, usize1) => (read_value!($next, usize) - 1);
+    ($next:expr, $t:ty) => ($next().parse::<$t>().expect("Parse error"));
+}
+
+fn main() {
+    let out = std::io::stdout();
+    let mut out = BufWriter::new(out.lock());
+    macro_rules! puts {($($format:tt)*) => (let _ = write!(out,$($format)*););}
+    input! {
+        n: usize,
+        qr: [(i64, i64); n],
+        q: usize,
+        td: [(usize1, i64); q],
+    }
+    for (t, d) in td {
+        let (q, r) = qr[t];
+        let x = (d + q - r - 1) / q;
+        puts!("{}\n", x * q + r);
+    }
+}
diff --git a/atcoder/abc378/c.rs b/atcoder/abc378/c.rs
new file mode 100644
index 00000000..2e714619
--- /dev/null
+++ b/atcoder/abc378/c.rs
@@ -0,0 +1,56 @@
+use std::collections::*;
+use std::io::{Write, BufWriter};
+// https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
+macro_rules! input {
+    ($($r:tt)*) => {
+        let stdin = std::io::stdin();
+        let mut bytes = std::io::Read::bytes(std::io::BufReader::new(stdin.lock()));
+        let mut next = move || -> String{
+            bytes.by_ref().map(|r|r.unwrap() as char)
+                .skip_while(|c|c.is_whitespace())
+                .take_while(|c|!c.is_whitespace())
+                .collect()
+        };
+        input_inner!{next, $($r)*}
+    };
+}
+
+macro_rules! input_inner {
+    ($next:expr) => {};
+    ($next:expr,) => {};
+    ($next:expr, $var:ident : $t:tt $($r:tt)*) => {
+        let $var = read_value!($next, $t);
+        input_inner!{$next $($r)*}
+    };
+}
+
+macro_rules! read_value {
+    ($next:expr, [ $t:tt ; $len:expr ]) => {
+        (0..$len).map(|_| read_value!($next, $t)).collect::<Vec<_>>()
+    };
+    ($next:expr, $t:ty) => ($next().parse::<$t>().expect("Parse error"));
+}
+
+fn main() {
+    let out = std::io::stdout();
+    let mut out = BufWriter::new(out.lock());
+    macro_rules! puts {($($format:tt)*) => (let _ = write!(out,$($format)*););}
+    macro_rules! putvec {
+        ($v:expr) => {
+            for i in 0..$v.len() {
+                puts!("{}{}", $v[i], if i + 1 == $v.len() {"\n"} else {" "});
+            }
+        }
+    }
+    input! {
+        n: usize,
+        a: [i64; n],
+    }
+    let mut hm = HashMap::new();
+    let mut b = vec![0; n];
+    for i in 0..n {
+        b[i] = hm.get(&a[i]).map_or(-1, |x| *x);
+        hm.insert(a[i], i as i64 + 1);
+    }
+    putvec!(b);
+}
diff --git a/atcoder/abc378/d.rs b/atcoder/abc378/d.rs
new file mode 100644
index 00000000..f178d167
--- /dev/null
+++ b/atcoder/abc378/d.rs
@@ -0,0 +1,73 @@
+// https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
+macro_rules! input {
+    ($($r:tt)*) => {
+        let stdin = std::io::stdin();
+        let mut bytes = std::io::Read::bytes(std::io::BufReader::new(stdin.lock()));
+        let mut next = move || -> String{
+            bytes.by_ref().map(|r|r.unwrap() as char)
+                .skip_while(|c|c.is_whitespace())
+                .take_while(|c|!c.is_whitespace())
+                .collect()
+        };
+        input_inner!{next, $($r)*}
+    };
+}
+
+macro_rules! input_inner {
+    ($next:expr) => {};
+    ($next:expr,) => {};
+    ($next:expr, $var:ident : $t:tt $($r:tt)*) => {
+        let $var = read_value!($next, $t);
+        input_inner!{$next $($r)*}
+    };
+}
+
+macro_rules! read_value {
+    ($next:expr, [ $t:tt ; $len:expr ]) => {
+        (0..$len).map(|_| read_value!($next, $t)).collect::<Vec<_>>()
+    };
+    ($next:expr, chars) => {
+        read_value!($next, String).chars().collect::<Vec<char>>()
+    };
+    ($next:expr, $t:ty) => ($next().parse::<$t>().expect("Parse error"));
+}
+
+fn rec(i: usize, j: usize, k: i32, s: &mut [Vec<char>]) -> i32 {
+    let h = s.len();
+    let w = s[0].len();
+    if s[i][j] != '.' {
+        return 0;
+    }
+    if k == 0 {
+        return 1;
+    }
+    s[i][j] = 'x';
+    let mut ret = 0;
+    for d in 0..4 {
+        let ni = i as i64 + [0, 1, 0, -1][d];
+        let nj = j as i64 + [1, 0, -1, 0][d];
+        if ni >= 0 && ni < h as i64 && nj >= 0 && nj < w as i64 {
+            ret += rec(ni as usize, nj as usize, k - 1, s);
+        }
+    }
+    s[i][j] = '.';
+    ret
+}
+
+fn main() {
+    input! {
+        h: usize, w: usize, k: i32,
+        s: [chars; h],
+    }
+    let mut s = s;
+    let mut ans = 0;
+    for i in 0..h {
+        for j in 0..w {
+            if s[i][j] == '#' {
+                continue;
+            }
+            ans += rec(i, j, k, &mut s);
+        }
+    }
+    println!("{}", ans)
+}
diff --git a/atcoder/abc378/e.rs b/atcoder/abc378/e.rs
new file mode 100644
index 00000000..fa426db6
--- /dev/null
+++ b/atcoder/abc378/e.rs
@@ -0,0 +1,108 @@
+// https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
+macro_rules! input {
+    ($($r:tt)*) => {
+        let stdin = std::io::stdin();
+        let mut bytes = std::io::Read::bytes(std::io::BufReader::new(stdin.lock()));
+        let mut next = move || -> String{
+            bytes.by_ref().map(|r|r.unwrap() as char)
+                .skip_while(|c|c.is_whitespace())
+                .take_while(|c|!c.is_whitespace())
+                .collect()
+        };
+        input_inner!{next, $($r)*}
+    };
+}
+
+macro_rules! input_inner {
+    ($next:expr) => {};
+    ($next:expr,) => {};
+    ($next:expr, $var:ident : $t:tt $($r:tt)*) => {
+        let $var = read_value!($next, $t);
+        input_inner!{$next $($r)*}
+    };
+}
+
+macro_rules! read_value {
+    ($next:expr, [ $t:tt ; $len:expr ]) => {
+        (0..$len).map(|_| read_value!($next, $t)).collect::<Vec<_>>()
+    };
+    ($next:expr, $t:ty) => ($next().parse::<$t>().expect("Parse error"));
+}
+
+// Segment Tree. This data structure is useful for fast folding on intervals of an array
+// whose elements are elements of monoid I. Note that constructing this tree requires the identity
+// element of I and the operation of I.
+// Verified by: yukicoder No. 2220 (https://yukicoder.me/submissions/841554)
+struct SegTree<I, BiOp> {
+    n: usize,
+    orign: usize,
+    dat: Vec<I>,
+    op: BiOp,
+    e: I,
+}
+
+impl<I, BiOp> SegTree<I, BiOp>
+    where BiOp: Fn(I, I) -> I,
+          I: Copy {
+    pub fn new(n_: usize, op: BiOp, e: I) -> Self {
+        let mut n = 1;
+        while n < n_ { n *= 2; } // n is a power of 2
+        SegTree {n: n, orign: n_, dat: vec![e; 2 * n - 1], op: op, e: e}
+    }
+    // ary[k] <- v
+    pub fn update(&mut self, idx: usize, v: I) {
+        debug_assert!(idx < self.orign);
+        let mut k = idx + self.n - 1;
+        self.dat[k] = v;
+        while k > 0 {
+            k = (k - 1) / 2;
+            self.dat[k] = (self.op)(self.dat[2 * k + 1], self.dat[2 * k + 2]);
+        }
+    }
+    // [a, b) (half-inclusive)
+    // http://proc-cpuinfo.fixstars.com/2017/07/optimize-segment-tree/
+    #[allow(unused)]
+    pub fn query(&self, rng: std::ops::Range<usize>) -> I {
+        let (mut a, mut b) = (rng.start, rng.end);
+        debug_assert!(a <= b);
+        debug_assert!(b <= self.orign);
+        let mut left = self.e;
+        let mut right = self.e;
+        a += self.n - 1;
+        b += self.n - 1;
+        while a < b {
+            if (a & 1) == 0 {
+                left = (self.op)(left, self.dat[a]);
+            }
+            if (b & 1) == 0 {
+                right = (self.op)(self.dat[b - 1], right);
+            }
+            a = a / 2;
+            b = (b - 1) / 2;
+        }
+        (self.op)(left, right)
+    }
+}
+
+fn main() {
+    input! {
+        n: usize, m: usize,
+        a: [usize; n],
+    }
+    let mut acc = vec![0; n + 1];
+    for i in 0..n {
+        acc[i + 1] = (acc[i] + a[i]) % m;
+    }
+    let mut st = SegTree::new(m, |x, y| x + y, 0i64);
+    let mut mcount = 0;
+    for i in 0..n + 1 {
+        mcount += st.query(acc[i] + 1..m);
+        let val = st.query(acc[i]..acc[i] + 1);
+        st.update(acc[i], val + 1);
+    }
+    let mut ans = m as i64 * mcount;
+    for i in 0..n + 1 {
+        ans += acc[i] as i64 * (2 * i as i64 - n as i64);
+    }
+    println!("{}", ans);
+}
diff --git a/atcoder/abc378/f.rs b/atcoder/abc378/f.rs
new file mode 100644
index 00000000..70e1f268
--- /dev/null
+++ b/atcoder/abc378/f.rs
@@ -0,0 +1,149 @@
+// https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
+macro_rules! input {
+    ($($r:tt)*) => {
+        let stdin = std::io::stdin();
+        let mut bytes = std::io::Read::bytes(std::io::BufReader::new(stdin.lock()));
+        let mut next = move || -> String{
+            bytes.by_ref().map(|r|r.unwrap() as char)
+                .skip_while(|c|c.is_whitespace())
+                .take_while(|c|!c.is_whitespace())
+                .collect()
+        };
+        input_inner!{next, $($r)*}
+    };
+}
+
+macro_rules! input_inner {
+    ($next:expr) => {};
+    ($next:expr,) => {};
+    ($next:expr, $var:ident : $t:tt $($r:tt)*) => {
+        let $var = read_value!($next, $t);
+        input_inner!{$next $($r)*}
+    };
+}
+
+macro_rules! read_value {
+    ($next:expr, ( $($t:tt),* )) => { ($(read_value!($next, $t)),*) };
+    ($next:expr, [ $t:tt ; $len:expr ]) => {
+        (0..$len).map(|_| read_value!($next, $t)).collect::<Vec<_>>()
+    };
+    ($next:expr, usize1) => (read_value!($next, usize) - 1);
+    ($next:expr, $t:ty) => ($next().parse::<$t>().expect("Parse error"));
+}
+
+// Union-Find tree.
+// Verified by https://atcoder.jp/contests/pakencamp-2019-day3/submissions/9253305
+struct UnionFind { disj: Vec<usize>, rank: Vec<usize> }
+
+impl UnionFind {
+    fn new(n: usize) -> Self {
+        let disj = (0..n).collect();
+        UnionFind { disj: disj, rank: vec![1; n] }
+    }
+    fn root(&mut self, x: usize) -> usize {
+        if x != self.disj[x] {
+            let par = self.disj[x];
+            let r = self.root(par);
+            self.disj[x] = r;
+        }
+        self.disj[x]
+    }
+    fn unite(&mut self, x: usize, y: usize) {
+        let mut x = self.root(x);
+        let mut y = self.root(y);
+        if x == y { return }
+        if self.rank[x] > self.rank[y] {
+            std::mem::swap(&mut x, &mut y);
+        }
+        self.disj[x] = y;
+        self.rank[y] += self.rank[x];
+    }
+    #[allow(unused)]
+    fn is_same_set(&mut self, x: usize, y: usize) -> bool {
+        self.root(x) == self.root(y)
+    }
+    #[allow(unused)]
+    fn size(&mut self, x: usize) -> usize {
+        let x = self.root(x);
+        self.rank[x]
+    }
+}
+
+fn main() {
+    // In order to avoid potential stack overflow, spawn a new thread.
+    let stack_size = 104_857_600; // 100 MB
+    let thd = std::thread::Builder::new().stack_size(stack_size);
+    thd.spawn(|| solve()).unwrap().join().unwrap();
+}
+
+fn solve() {
+    input! {
+        n: usize,
+        uv: [(usize1, usize1); n - 1],
+    }
+    let mut g = vec![vec![]; n];
+    for &(u, v) in &uv {
+        g[u].push(v);
+        g[v].push(u);
+    }
+    let mut ex2 = vec![];
+    let mut exindex = vec![n * 2; n];
+    for i in 0..n {
+        if g[i].len() == 2 {
+            exindex[i] = ex2.len();
+            ex2.push(i);
+        }
+    }
+    let ext_idx = |v: usize, to: usize| -> usize {
+        assert_eq!(g[v].len(), 2);
+        let u = g[v][0];
+        if u == to {
+            return v;
+        }
+        assert_eq!(g[v][1], to);
+        n + exindex[v]
+    };
+    let mut uf = UnionFind::new(n + ex2.len());
+    for i in 0..n {
+        if g[i].len() != 2 && g[i].len() != 3 {
+            continue;
+        }
+        if g[i].len() == 3 {
+            for &w in &g[i] {
+                if g[w].len() == 3 {
+                    uf.unite(i, w);
+                }
+            }
+            continue;
+        }
+        assert_eq!(g[i].len(), 2);
+        let u = g[i][0];
+        let v = g[i][1];
+        let mut con = |x: usize, y: usize| {
+            assert_eq!(g[x].len(), 2);
+            let xidx = ext_idx(x, y);
+            if g[y].len() == 3 {
+                uf.unite(xidx, y);
+                return;
+            }
+            if g[y].len() != 2 {
+                return;
+            }
+            return;
+        };
+        con(i, u);
+        con(i, v);
+    }
+    let mut twos = vec![0i64; n + ex2.len()];
+    for i in 0..n + ex2.len() {
+        let ok = if i < n { g[i].len() == 2 } else { true };
+        if ok {
+            twos[uf.root(i)] += 1;
+        }
+    }
+    let mut ans = 0i64;
+    for v in twos {
+        ans += v * (v - 1) / 2;
+    }
+    println!("{}", ans);
+}
diff --git a/atcoder/abc378/remain.txt b/atcoder/abc378/remain.txt
new file mode 100644
index 00000000..01058d84
--- /dev/null
+++ b/atcoder/abc378/remain.txt
@@ -0,0 +1 @@
+g