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.*;
import java.math.*;
import java.lang.*;
import java.io.*;
 
public class Main{
  public static void main(String args[]) throws IOException{
    Scanner s=new Scanner(System.in);
   
    int n=s.nextInt();
   int k=s.nextInt();
    
    String ss=s.next();
    
    System.out.println(ss.substring(0,k-1)+(char)(ss.charAt(k-1)+32)+ss.substring(k));
  }
}