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. 
// Born Sinner
// old but im not that old
// fuck all you hoes get a grip
import java.util.*;
import java.lang.*;
import java.io.*;

public class codeforces
{
    static class FastReader{
        BufferedReader br;
        StringTokenizer st;
        public FastReader(){
            br = new BufferedReader(new InputStreamReader(System.in));
        }
        String next(){
            while(st == null || !st.hasMoreElements()){
                try{
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e){
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }
        int nextInt(){
            return Integer.parseInt(next());
        }
        long nextLong(){
            return Long.parseLong(next());
        }
        double nextDouble(){
            return Double.parseDouble(next());
        }
        String nextLine(){
            String str = "";
            try{
                str = br.readLine();
            } catch (Exception e){
                e.printStackTrace();
            }
            return str;
        }
    }
    static int modPower(int x, int y, int mod){
        int res = 1;
        x %= mod;
        if(x==0) return 0;
        while(y>0){
            if(y%2==1){
                res = (res*x)%mod;
            }
            y = y>>1;
            x = (x*x)%mod;
        }
        return res;
    }
    static class pair<T1, T2>{
        T1 first;
        T2 second;
        pair(T1 first, T2 second){
            this.first = first;
            this.second = second;
        }
    }
    
    public static void main (String[] args) throws java.lang.Exception
    {
        FastReader in = new FastReader();
        int t = in.nextInt();
        while(t-->0){
            int n = in.nextInt();
            String s = in.next();
            String ans = "";
            for(int i = 0; i < n; i++){
                String x = s.substring(i, n+i);
                System.out.print(x.charAt(i));
            }
            System.out.println();
        }
    }
}
