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.*;

class Main{
    public static void main(String[] args) {
        Scanner sc = new  Scanner(System.in);
        int N = sc.nextInt();
        int K = sc.nextInt();
        String S = sc.next();

        String[] str = S.split("", -1);
        for (int i=0;i<N;i++){
            if(i==K-1){
                if(str[i].equals("A")){
                    System.out.print("a");
                } else if (str[i].equals("B")){
                    System.out.print("b");
                } else if (str[i].equals("C")){
                    System.out.print("c");
                }
            }else{
                System.out.print(str[i]);
            }
        }
        sc.close();
    }
}