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.BufferedWriter;
import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Scanner;
import java.util.Arrays;
import java.io.*;
import java.util.*;
public final class hackerearth {
 
public static void main (String []args) throws Exception{
	Reader r=new Reader();
	Scanner sc=new Scanner(System.in);
	Writer wr=new Writer();
    int t= sc.nextInt();
    while(t-->0) {
   	 int n = sc.nextInt();
   	 String s=sc.next();
   	 StringBuffer sb=new StringBuffer("");
   	 for(int i=0;i<s.length();i++){
   	     if(i%2==0)
   	     sb.append(s.charAt(i));
   	 }
   	 System.out.println(sb.toString());
}
}
}
 
class Reader
{
   final private int BUFFER_SIZE = 1 << 16;
   private DataInputStream din;
   private byte[] buffer;
   private int bufferPointer, bytesRead;
 
   public Reader()
   {
       din = new DataInputStream(System.in);
       buffer = new byte[BUFFER_SIZE];
       bufferPointer = bytesRead = 0;
   }
 
   public Reader(String file_name) throws IOException
   {
       din = new DataInputStream(new FileInputStream(file_name));
       buffer = new byte[BUFFER_SIZE];
       bufferPointer = bytesRead = 0;
   }
 
   public String readLine() throws IOException
   {
       byte[] buf = new byte[64]; // line length
       int cnt = 0, c;
       while ((c = read()) != -1)
       {
           if (c == '\n')
               break;
           buf[cnt++] = (byte) c;
       }
       return new String(buf, 0, cnt);
   }
 
   public int nextInt() throws IOException
   {
       int ret = 0;
       byte c = read();
       while (c <= ' ')
           c = read();
       boolean neg = (c == '-');
       if (neg)
           c = read();
       do
       {
           ret = ret * 10 + c - '0';
       }  while ((c = read()) >= '0' && c <= '9');
 
       if (neg)
           return -ret;
       return ret;
   }
 
   public long nextLong() throws IOException
   {
       long ret = 0;
       byte c = read();
       while (c <= ' ')
           c = read();
       boolean neg = (c == '-');
       if (neg)
           c = read();
       do {
           ret = ret * 10 + c - '0';
       }
       while ((c = read()) >= '0' && c <= '9');
       if (neg)
           return -ret;
       return ret;
   }
 
   public double nextDouble() throws IOException
   {
       double ret = 0, div = 1;
       byte c = read();
       while (c <= ' ')
           c = read();
       boolean neg = (c == '-');
       if (neg)
           c = read();
 
       do {
           ret = ret * 10 + c - '0';
       }
       while ((c = read()) >= '0' && c <= '9');
 
       if (c == '.')
       {
           while ((c = read()) >= '0' && c <= '9')
           {
               ret += (c - '0') / (div *= 10);
           }
       }
 
       if (neg)
           return -ret;
       return ret;
   }
 
   private void fillBuffer() throws IOException
   {
       bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
       if (bytesRead == -1)
           buffer[0] = -1;
   }
 
   private byte read() throws IOException
   {
       if (bufferPointer == bytesRead)
           fillBuffer();
       return buffer[bufferPointer++];
   }
 
   public void close() throws IOException
   {
       if (din == null)
           return;
       din.close();
   }
}
 
	 class Writer{
	
	BufferedWriter wr =  null;
	
	Writer(){}
	
	public Writer(BufferedWriter wr) {
		this.wr = wr;
	}
 
	public void writeInt(int value) throws IOException {
		wr.write(value + "\n");
	}
	
	public void writeString(String value) throws IOException {
		wr.write(value + "\n");
	}
	
	public void flush() throws IOException {
		wr.flush();
		wr.close();
	}
}