백준 2675번

import java.util.Scanner;

public class Main2675 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int tc = sc.nextInt();
        
        for(int i = 0; i < tc; i++){
            int r = sc.nextInt();
            String str = sc.next();

            System.out.println(repeat(r, str));
        }
    }

    public static String repeat(int r, String str){
        String s = "";

        for(int i = 0; i < str.length(); i++){
            char c = str.charAt(i);
            for(int j = 0; j < r; j++){
                s += c;
            }
        }
        return s;
    }
}