Problem:
Score : 200 points

Problem Statement

You are given a string S of length N consisting of lowercase English letters, and an integer K.
Print the string obtained by replacing every character in S that differs from the K-th character of S, with *.

Constraints

1 \leq K \leq N\leq 10

S is a string of length N consisting of lowercase English letters.

N and K are integers.

Input

Input is given from Standard Input in the following format:

N
S
K

Output

Print the string obtained by replacing every character in S that differs from the K-th character of S, with *.

Sample Input 1

5
error
2

Sample Output 1

*rr*r

The second character of S is r. When we replace every character in error that differs from r with *, we get the string *rr*r.

Sample Input 2

6
eleven
5

Sample Output 2

e*e*e*

Sample Input 3

9
education
7

Sample Output 3

******i**

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

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

public class Hello
{
    private const ulong MOD9 = 1000000007;

    public static void Main()
    {
        // var nq = Console.ReadLine().Split(' ');
        var n = int.Parse(Console.ReadLine());
        var s = new System.Text.StringBuilder(Console.ReadLine());
        var k = int.Parse(Console.ReadLine());

        var c = s[k - 1];

        for (int i = 0, count = s.Length; i < count; ++i)
        {
            if (s[i] != c)
                s[i] = '*';
        }

        Console.WriteLine(s);
    }
}