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)

namespace ABC126_A
{
    using static System.Console;
    using System.Linq;
    using System.Collections.Generic;

    public class Program
    {
        static void Main(string[] args)
        {
            var k = ReadInputsAsInt().Last();

            WriteLine(Solve(ReadLine(), k));
        }

        public static string Solve(string s, int k)
        {
            var r = s.ToCharArray();
            r[k - 1] = char.ToLower(s[k - 1]);

            return new string(r);
        }

        static IEnumerable<int> ReadInputsAsInt() => ReadLine().Split(' ').Select(x => int.Parse(x));
    }
}