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>
#include <stdlib.h>
#include <string.h>

int main(){
    int N, K;
    char s[51];
    scanf("%d %d", &N, &K);
    getchar();//改行読み捨て
    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\n",s);
    return 0;
}