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 static System.Console;
class program{
  static void Main(string[] args){
    program p = new program();
    p.Run();
  }
  void Run(){
	int n = int.Parse(ReadLine());
    string s = ReadLine();
    int k = int.Parse(ReadLine());
    string ks = s.Substring(k-1,1);
    int i=0;
    while(i<n){
      if (s.Substring(i,1)!=ks){
        s=s.Remove(i)+"*"+s.Remove(0,i+1);
      }
      i++;
    }
    WriteLine(s);
  }
}