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)

//changing a charactor
#include<stdio.h>
#define NUM 50
int main(){
    int n,k;
    char s[NUM];

    //文字数 変換する文字
    scanf("%d %d",&n,&k);

    scanf("%s",s);
    for(int i=0;i<n;i++){
        if(i==k-1){
            s[i]+=0x20;
        }
    }
    printf("%s",s);
    putchar('\n');
    return 0;
}