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.Map.Entry;
public class Main {
	static long mod = (long) (1e9+7);
	public static void main(String[] args) throws IOException 
    { 
        StdIn scn = new StdIn();
        int t = scn.nextInt();
        //int t = 1;
        while (t-- > 0) {
        	int n = scn.nextInt();
        	String str = scn.nextLine();
        	for (int i = 0; i<2*n-1; i+=2) {
        		System.out.print(str.charAt(i));
        	}
        	System.out.println();
        }
    } 
    interface Input {
    	public String next();
    	public String nextLine();
    	public int nextInt();
    	public long nextLong();
    	public double nextDouble();
    }
    static class StdIn implements Input {
    	final private int BUFFER_SIZE = 1 << 16;
    	private DataInputStream din;
    	private byte[] buffer;
    	private int bufferPointer, bytesRead;

    	public StdIn() {
    		din = new DataInputStream(System.in);
    		buffer = new byte[BUFFER_SIZE];
    		bufferPointer = bytesRead = 0;
    	}
    	
    	public StdIn(String filename) {
    		try{
    			din = new DataInputStream(new FileInputStream(filename));
    		} catch(Exception e) {
    			throw new RuntimeException();
    		}
    		buffer = new byte[BUFFER_SIZE];
    		bufferPointer = bytesRead = 0;
    	}
    	
    	public String next() {
    		int c;
    		while((c=read())!=-1&&(c==' '||c=='\n'||c=='\r'));
    		StringBuilder s = new StringBuilder();
    		while (c != -1)
    		{
    			if (c == ' ' || c == '\n'||c=='\r')
    				break;
    			s.append((char)c);
    			c=read();
    		}
    		return s.toString();
    	}

    	public String nextLine() {
    		int c;
    		while((c=read())!=-1&&(c==' '||c=='\n'||c=='\r'));
    		StringBuilder s = new StringBuilder();
    		while (c != -1)
    		{
    			if (c == '\n'||c=='\r')
    				break;
    			s.append((char)c);
    			c = read();
    		}
    		return s.toString();
    	}

    	public int nextInt() {
    		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 int[] readIntArray(int n) {
    		int[] ar = new int[n];
    		for(int i=0; i<n; ++i)
    			ar[i]=nextInt();
    		return ar;
    	}

    	public long nextLong() {
    		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 long[] readLongArray(int n) {
    		long[] ar = new long[n];
    		for(int i=0; i<n; ++i)
    			ar[i]=nextLong();
    		return ar;
    	}
    	
    	public long power(long base, long exp) {
    		long res = 1;
    		base = base%mod;
    		if (base == 0) return 0;
    		while (exp>0) {
    			if ((exp & 1) == 1) {
    				res = (res*base)%mod;
    			}
    			exp = exp>>1;
    			base = (base*base)%mod;
    		}
    		return res;
    	}
    	
    	public double nextDouble() {
    		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() {
    		try{
    			if (bufferPointer == bytesRead)
    				fillBuffer();
    			return buffer[bufferPointer++];
    		} catch(IOException e) {
    			throw new RuntimeException();
    		}
    	}

    	public void close() throws IOException {
    		if (din == null)
    			return;
    		din.close();
    	}
    }
 }