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;

namespace ABC126
{
	class Program
	{
		static void Main(String[] args)
		{
			// 入力
			int[] info = Array.ConvertAll(Console.ReadLine().Split(' '),int.Parse);
			char[] S = Console.ReadLine().ToCharArray();
			// 解く
			if (info.Length>=2 && info[1]>=1 && info[1]<=S.Length)
			{
				int index = info[1] - 1;
				S[index] = Char.ToLower(S[index]);
			}
			// 出力
			Console.WriteLine(S);
		}
	}
}