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;

namespace AtCoder
{
    class Program
    {
        static void Main(string[] args)
        {
            //[summary]B - *e**** ********e* *e****e* ****e**
            int n = int.Parse(Console.ReadLine());
            string s = Console.ReadLine();
            int k = int.Parse(Console.ReadLine()) - 1;

            var chars = s.ToCharArray().Distinct().ToList();
            
            foreach(var c in chars)
            {
                if (c != s[k])
                {
                    s = s.Replace(c, '*');
                }
            }

            Console.WriteLine(s);
        }
    }
}