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

namespace Algorithm
{
    class Program
    {
        static void Main(string[] args)
        {
            var line = Console.ReadLine().Split().Select(z => int.Parse(z)).ToArray();
            int n = line[0], k = line[1];

            var cArray = Console.ReadLine().ToCharArray();

            cArray[k - 1] = Convert.ToChar(cArray[k - 1].ToString().ToLower());

            Console.WriteLine(new string(cArray));
        }

    }
}