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 Java7 (OpenJDK 1.7.0) (judge verdict: Accepted)

import java.io.*;

class Main
{
	public static void main (String[] args) throws java.lang.Exception
	{
		BufferedReader r = new BufferedReader (new InputStreamReader (System.in));
		String s1 = r.readLine();
		int index = Integer.valueOf(s1.split(" ")[1]) - 1;
		char[] s2 = r.readLine().toCharArray();
		char c = s2[index];
		s2[index] = Character.isUpperCase(c) ? Character.toLowerCase(c) : Character.toUpperCase(c);
		System.out.println(new String(s2));
	}
}