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;

public class Main {

    private static Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        int n = sc.nextInt();
        int k = sc.nextInt();
        String s = sc.next();
        String[] sl = s.split("");
        if (sl[k-1].equals("A")) {
            sl[k-1] = "a";
        } else if (sl[k-1].equals("B")) {
            sl[k-1] = "b";
        } else if (sl[k-1].equals("C")) {
            sl[k-1] = "c";
        }
        System.out.println(String.join("", sl));
    }

}