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: Runtime Error)

import java.util.Scanner;

public class Main{

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = Integer.parseInt(sc.nextLine());
		int k = Integer.parseInt(sc.nextLine())-1;
		String s = sc.nextLine();

		String[] spl = s.split("");
		StringBuilder sb = new StringBuilder();
		for(int i = 0; i < n;i++){
			if(i == k){
				sb.append(spl[i].toLowerCase());
			}else{
				sb.append(spl[i]);
			}
		}
		System.out.println(sb);
	}
}