def mutate_string(string, position, character):
    return string[:position]+character+string[position+1:]

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

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

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


s = input()
i, c = input().split()
s_new = mutate_string(s, int(i), c)
print(s_new)