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.util.*;
 
public class acmp{
	static Scanner in = new Scanner(System.in);
		// int days = in.nextInt();
		// int[] array = new int[total];
		// for(int i = 0; i<total; i++){
		// 	array[i] = in.nextInt();
		// }

		// int min = Integer.MAX_VALUE;
  		// int max = Integer.MIN_VALUE;
 	
	public static void main(String[] args) {
		//zhan
		//dos
		//md
		int test = in.nextInt();
		while(test>0){
			solve();
			test--;
		}
	}

	public static void solve(){
		List<String> list = new ArrayList<>();

		int n = in.nextInt();
		String s = in.next();

		int r = n;
		int l = 0;
		while(r <= (2*n-1)){
			list.add(s.substring(l, r));
			l++; r++;
		}
		StringBuilder sb = new StringBuilder();
		int i = 0;
		while(i != n && !list.isEmpty()){
			char c = list.get(0).charAt(i);
			for(int j = 0; j<list.size(); j++){
				if(list.get(j).charAt(i) == c){
					list.remove(j);
				}
			}
			sb.append(c+"");
			i++;
		}
		if(i != n){
			while(i != n){
				sb.append(0 + "");
				i++;
			}
		}
		System.out.println(sb.toString());
		
	}
}