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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;


public class Main {

	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String[] tmp = br.readLine().split(" ");

		int N = Integer.parseInt(tmp[0]);
		int K = Integer.parseInt(tmp[1]);

		String S = br.readLine();

		for(int i = 0;i<N;i++){
			if(i+1 == K){
				int a = (int)S.charAt(i) + 32;
				byte[] ascii = {Byte.parseByte(String.valueOf(a))};
				String resultString = new String(ascii, "US-ASCII");
				System.out.print(resultString);
			}else{
				System.out.print(S.charAt(i));
			}
		}



	}

}