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 Java (OpenJDK 11.0.6) (judge verdict: Accepted)

import java.util.Locale;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner scan=new Scanner(System.in);
		int n=scan.nextInt();
		int k=scan.nextInt();
		scan.nextLine();
		String s= scan.nextLine();
		String t="";
		for(int i=0;i<n;i++) {
			if(i==k-1) {
			t+=s.toLowerCase().charAt(i);
			}
			else {
				t+=s.charAt(i);
			}
		}
		System.out.println(t);
	

}
}