[백준] 2675번

import java.util.*;
import java.io.*;
import java.math.*;

public class Main {
   public static void main(String[] args) {
      Scanner sc = new Scanner(System.in);

      int T = sc.nextInt();

      for (int i = 0; i < T; i++) {
         int count = sc.nextInt();
         String data = sc.next();

         for (int j = 0; j < data.length(); j++) {
            for (int k = 0; k < count; k++) {
               System.out.print(data.charAt(j));
            }
         }
         System.out.println();
      }
   }
}