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;

class Main {
  public static void main(String[] args) {
    Scanner stdIn = new Scanner(System.in);
    int n = stdIn.nextInt();
    int k = stdIn.nextInt();
    String s = stdIn.next();

    s = s.substring(0,k-1) + (s.substring(k-1,k)).toLowerCase() + s.substring(k,n);

    System.out.println(s);
  }
}