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

namespace Program
{
    interface Output
    {
        void Write(object str);
        void WriteLine(object str);
    }

    interface Input
    {
        int NextInt();
        string NextString();
    }

    class Console_ : Input, Output
    {
        Queue<string> param = new Queue<string>();
        int Input.NextInt()
        {
            if (param.Count == 0)
            {
                foreach (var item in Console.ReadLine().Split(' '))
                {
                    param.Enqueue(item);
                }
            }
            return int.Parse(param.Dequeue());
        }
        string Input.NextString()
        {
            if (param.Count == 0)
            {
                foreach (var item in Console.ReadLine().Split(' '))
                {
                    param.Enqueue(item);
                }
            }
            return param.Dequeue();
        }
        void Output.Write(object str)
        {
            System.Console.Write(str.ToString());
        }
        void Output.WriteLine(object str)
        {
            System.Console.WriteLine(str.ToString());
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            new Solver(new Console_(), new Console_()).Run();
        }
    }

    class Debug_ : Input
    {
        int i = 0;
        int Input.NextInt()
        {
            return (int)data[i++];
        }
        string Input.NextString()
        {
            return (string)data[i++];
        }
        object[] data =
        {
            "abcdefghijklmnopqrstuvwxyz",
            "abcdefghijklmnopqrstuavwxyz",
            "abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz"
        };
    }

    class Solver
    {
        Input input;
        Output output;
        public Solver(Input input, Output output)
        {
            this.input = input;
            this.output = output;
        }

        public void Run()
        {
            var N = input.NextInt();
            var S = input.NextString().ToArray();
            var K = input.NextInt();
            for (int i = 0; i < S.Length; ++i)
            {
                S[i] = S[i] != S[K - 1] ? '*' : S[i];
            }
            output.WriteLine(new string(S));
        }
    }
}