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 (Clang 3.8.0) (judge verdict: Accepted)

    #include<stdio.h>
    int main()
    {
        int a,b,c;
        char s[101];
        // 整数の入力
        scanf("%d", &a);
        scanf("%d", &b);
      	b=b-1;
        // 文字列の入力
        scanf("%s",s);
        if(s[b]=='A'){
          s[b]='a';     
        }else if(s[b]=='B'){
          s[b]='b';
        }else{
          s[b]='c';
        }
        // 出力
        printf("%s",s);
        return 0;
    }