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.util.Scanner;
import java.util.Arrays;
import java.util.Collections;

public class Main {
    public static void main(String[] args) {
       Scanner sc = new Scanner(System.in);
//       while(true) {
    	   int n = sc.nextInt();
    	   int k = sc.nextInt();
    	   String s = sc.next();
    	   if(k==1) 
    		   s = s.substring(0, 1).toLowerCase()+s.substring(1);
    	   else
    		   s = s.substring(0, k-1)+s.substring(k-1, k).toLowerCase()+s.substring(k);
    	   System.out.println(s);
//      }
    }
}