A binary string is a string where each character is either 0 or 1. Two binary strings a and b of equal length are similar, if they have the same character in some position (there exists an integer i such that a_i = b_i). For example:

  * 10010 and 01111 are similar (they have the same character in position 4); 
  * 10010 and 11111 are similar; 
  * 111 and 111 are similar; 
  * 0110 and 1001 are not similar. 



You are given an integer n and a binary string s consisting of 2n-1 characters. Let's denote s[l..r] as the contiguous substring of s starting with l-th character and ending with r-th character (in other words, s[l..r] = s_l s_{l + 1} s_{l + 2} ... s_r).

You have to construct a binary string w of length n which is similar to all of the following strings: s[1..n], s[2..n+1], s[3..n+2], ..., s[n..2n-1].

Input

The first line contains a single integer t (1 ≤ t ≤ 1000) — the number of test cases.

The first line of each test case contains a single integer n (1 ≤ n ≤ 50).

The second line of each test case contains the binary string s of length 2n - 1. Each character s_i is either 0 or 1.

Output

For each test case, print the corresponding binary string w of length n. If there are multiple such strings — print any of them. It can be shown that at least one string w meeting the constraints always exists.

Example

Input


4
1
1
3
00000
4
1110000
2
101


Output


1
000
1010
00

Note

The explanation of the sample case (equal characters in equal positions are bold):

The first test case: 

  * 1 is similar to s[1..1] = 1. 



The second test case: 

  * 000 is similar to s[1..3] = 000; 
  * 000 is similar to s[2..4] = 000; 
  * 000 is similar to s[3..5] = 000. 



The third test case: 

  * 1010 is similar to s[1..4] = 1110; 
  * 1010 is similar to s[2..5] = 1100; 
  * 1010 is similar to s[3..6] = 1000; 
  * 1010 is similar to s[4..7] = 0000. 



The fourth test case: 

  * 00 is similar to s[1..2] = 10; 
  * 00 is similar to s[2..3] = 01. 

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

import java.util.logging.Logger;

import static java.lang.System.*;

public class a{
    static BufferedReader br;
    static  long mod  = 998244353;
    static HashSet<Integer> p  = new HashSet<>();
    static   protected int a = 9;
    static    protected int b =10;

    public static void main(String[] args) throws Exception {
        br = new BufferedReader(new InputStreamReader(System.in));

        int testcCase = 1;



         testcCase=cinI();
             while(testcCase-->0){
                 int n  =cinI();
                 char[] s = cin().toCharArray();

                 for(int i=0;i<n;i++){
                     System.out.print(s[2*i]);
                 }
                 System.out.println();
             }










    }

    public static boolean legal(int x,int y,int[][] grid){

        if(x<0 || x>=a || y<0 || y>=b){

            return false;

        }
        if(grid[x][y]==1){
            return true;
        }
        else{
            return false;
        }

    }












    public static long min(long a,long b) {
        return Math.min(a,b);
    }
    public static int min(int a,int b) {
        return Math.min(a,b);
    }
    public  static  int[] readArray(int n,int x ,int z)throws Exception{
        int[] arr= new int[n];
        //   System.out.println(arr.length);
        String[] ar= cinA();
        for(int i =x ;i<n;i++){
            //   System.out.println(i-x);
            //  int  y  =getI(ar[i-x]);
            arr[i]=getI(ar[i-x]);
        }
        return arr;
    }
    public  static  long[] readArray(int n,int x )throws Exception{
        long[] arr= new long[n];
        String[] ar= cinA();
        for(int i =x ;i<n+x;i++){
            arr[i]=getL(ar[i-x]);
        }
        return arr;
    }

    public static void arrinit(String[] a,long[] b)throws Exception{
        for(int i=0;i<a.length;i++){
            b[i]=Long.parseLong(a[i]);
        }
    }
    public  static HashSet<Integer>[]  Graph(int n,int edge,int directed)throws Exception{
        HashSet<Integer>[] tree=  new HashSet[n];

        for(int j=0;j<edge;j++){

            String[] uv = cinA();
            int u = getI(uv[0]);
            int v = getI(uv[1]);
            if(directed==0){

                tree[v].add(u);
            }
            tree[u].add(v);
        }
        return tree;
    }
    public static void arrinit(String[] a,int[] b)throws Exception{
        for(int i=0;i<a.length;i++){
            b[i]=Integer.parseInt(a[i]);
        }
    }
    static double findRoots(int a, int b, int c) {
        // If a is 0, then equation is not
        //quadratic, but linear


        int d = b * b - 4 * a * c;
        double sqrt_val = Math.sqrt(Math.abs(d));


        // System.out.println("Roots are real and different \n");

        return Math.max((double) (-b + sqrt_val) / (2 * a),
                (double) (-b - sqrt_val) / (2 * a));


    }

    public static String cin() throws Exception {
        return br.readLine();
    }

    public static String[] cinA() throws Exception {
        return br.readLine().split(" ");
    }
    public static String[] cinA(int x) throws Exception{
        return br.readLine().split("");
    }

    public static String ToString(Long x) {
        return Long.toBinaryString(x);
    }

    public static void cout(String s) {
        System.out.println(s);
    }

    public static Integer cinI() throws Exception {
        return Integer.parseInt(br.readLine());
    }

    public static int getI(String s) throws Exception {
        return Integer.parseInt(s);
    }

    public static long getL(String s) throws Exception {
        return Long.parseLong(s);
    }

    public static long max(long a, long b) {
        return Math.max(a, b);
    }
    public static int max(int a, int b) {
        return Math.max(a, b);
    }

    public static void coutI(int x) {
        System.out.println(String.valueOf(x));
    }

    public static void coutI(long x) {
        System.out.println(String.valueOf(x));
    }

    public static Long cinL() throws Exception {
        return Long.parseLong(br.readLine());
    }

    public static void arrInit(String[] arr, int[] arr1) throws Exception {
        for (int i = 0; i < arr.length; i++) {
            arr1[i] = getI(arr[i]);
        }

    }
}
