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.Linq;

class Program {
    static void Main (string[] args) {
        var N = int.Parse (Console.ReadLine ());
        var S = Console.ReadLine ();
        var K = int.Parse (Console.ReadLine ()) - 1;
        Char[] ans = new Char[N];
        for (var i = 0; i < N; i++) {
            if (S[i] == S[K]) {
                ans[i] = S[i];
            } else {
                ans[i] = char.Parse ("*");

            }
        }

        foreach (var c in ans) Console.Write (c);
        Console.WriteLine ();
    }
}