change_letter_into_a_string

#We have seen that lists are mutable (they can be changed), and tuples are immutable (they cannot be changed).
#Let's try to understand this with an example.
#You are given an immutable string, and you want to make changes to it.
#example : >>> string = "abracadabra"
#>>> print string[5] ==> a
#to change the a --> k one solution is make this string a list and change the valie
#Another approach is to slice the string and join it back.
#>>> string = string[:5] + "k" + string[6:]
#sample input
#abracadabra
# 5 k

def mutate_string(string, position, character):
    list_string=list(string)
    list_string[position]=character
    string=''.join(list_string)
    return(string)

if __name__ == '__main__':
    s = input()
    i, c = input().split()
    s_new = mutate_string(s, int(i), c)
    print(s_new)