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: Runtime Error)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using BitArray = System.Collections.BitArray;
using BigInteger = System.Numerics.BigInteger;

namespace AtCoderProject
{
    class Program
    {
        static void Main()
        {
            Console.WriteLine(new Program().Calc());
        }

        public object Calc()
        {
            ReadLine();
            var input = ReadLine();
            var K = ReadLineInt32();
            var target = input[K];
            return new string(input.Select(c => c == target ? c : '*').ToArray());
        }


#if DEBUG
#pragma warning disable IDE0051 // 使用されていないプライベート メンバーを削除する
#pragma warning disable IDE1006 // 命名スタイル
        static string _ReadLineImpl() => queue.Dequeue();
#pragma warning restore IDE1006 // 命名スタイル
        static readonly Queue<string> queue;
        static Program()
        {
            string input = @"
9
.........
";
            queue = new Queue<string>();
            foreach (var line in input.Split(new char[] { '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries))
                queue.Enqueue(line);
        }
#else
        private static string _ReadLineImpl() => Console.ReadLine();
#endif
        static string ReadLine() => _ReadLineImpl();
        static int ReadLineInt32() => int.Parse(ReadLine());
        static long ReadLineInt64() => long.Parse(ReadLine());
        static ulong ReadLineUInt64() => ulong.Parse(ReadLine());
        static double ReadLineDouble() => double.Parse(ReadLine());
        static List<string> ReadLineSplit() => ReadLine().Split().ToList();
        static List<int> ReadLineSplitInt32() => ReadLine().Split().Select(s => int.Parse(s)).ToList();
        static List<long> ReadLineSplitInt64() => ReadLine().Split().Select(s => long.Parse(s)).ToList();
        static List<ulong> ReadLineSplitUInt64() => ReadLine().Split().Select(s => ulong.Parse(s)).ToList();
        static List<double> ReadLineSplitDouble() => ReadLine().Split().Select(s => double.Parse(s)).ToList();

        static IEnumerable<string> RepeatReadLines(int count)
        {
            for (int i = 0; i < count; i++)
                yield return ReadLine();
        }
        static IEnumerable<int> RepeatReadLinesInt32(int count)
        {
            for (int i = 0; i < count; i++)
                yield return ReadLineInt32();
        }
        static IEnumerable<List<string>> RepeatReadLinesSplit(int count)
        {
            for (int i = 0; i < count; i++)
                yield return ReadLineSplit();
        }
    }
    static class BitArrayUtils
    {
        static BitArray ToBitArray(this long l)
        {
            return new BitArray(BitConverter.GetBytes(l));
        }
        static long ToInt64(this BitArray bitArray)
        {
            var array = new byte[8];
            bitArray.CopyTo(array, 0);
            return BitConverter.ToInt64(array, 0);
        }
        static BitArray ToBitArray(this ulong l)
        {
            return new BitArray(BitConverter.GetBytes(l));
        }
        static ulong ToUInt64(this BitArray bitArray)
        {
            var array = new byte[8];
            bitArray.CopyTo(array, 0);
            return BitConverter.ToUInt64(array, 0);
        }
    }
}