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 (GCC 5.4.1) (judge verdict: Accepted)

#include <stdio.h>

int main()
{
    int n,k,i;
    scanf("%d %d",&n,&k);
    char s[n];
    for(i=0;i<=n;i++){
        scanf("%c",&s[i]);
        if(i==k){
            if(s[i] == 'A') s[i] = 'a';
            else if(s[i] == 'B') s[i] = 'b';
            else s[i] = 'c';
        }
    }
    for(i=1;i<=n;i++){
        printf("%c",s[i]);
    }
}