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 C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

public class MainClass
{
	public static void Main(string[] args)
	{
		string[] inputs = Console.ReadLine().Split(' ');
		int n = int.Parse(inputs[0]);
		int k = int.Parse(inputs[1]);
		string s = Console.ReadLine();
		for(int i = 0; i < s.Length;i++) {
		if(i==(k-1)) {
		Console.Write((char)(s[k-1] - 'A' +'a'));
		
		}else
		Console.Write(s[i]);
		
		
		}
		
		Console.WriteLine();
	}

	public static int Clamp(int val, int max, int min = 0)
	{
		return Math.Min(max, Math.Max(min, val));
	}


}