Problem:
Score : 100 points

Problem Statement

You are given a string S of length N consisting of A, B and C, and an integer K which is between 1 and N (inclusive).
Print the string S after lowercasing the K-th character in it.

Constraints

1 ≤ N ≤ 50

1 ≤ K ≤ N

S is a string of length N consisting of A, B and C.

Input

Input is given from Standard Input in the following format:

N K
S

Output

Print the string S after lowercasing the K-th character in it.

Sample Input 1

3 1
ABC

Sample Output 1

aBC

Sample Input 2

4 3
CABA

Sample Output 2

CAbA

Solution in C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <stdio.h>
int main(void){
    // Your code here!
    int N,K;
    char s[100];
    scanf("%d%d",&N,&K);
    scanf("%s",s);
    if(s[K-1]=='A'){
       s[K-1]='a'; 
    }else if(s[K-1]=='B'){
       s[K-1]='b'; 
    }else if(s[K-1]=='C'){
        s[K-1]='c';
    }
    printf("%s",s);
}
//https://atcoder.jp/contests/abc126/tasks/abc126_a