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.math.*;
import java.math.BigInteger;
public final class codeForces
{    
    public static void main(String args[])
    {
        StringBuilder ans=new StringBuilder();
        FastReader in=new FastReader();  
        int T=in.nextInt();
        while(T-->0)
        {
            int N=in.nextInt();
            
            String X=in.next();
            String w="";
            int j=0;
            for(int i=0; i<N; i++)
            {
                w+=X.charAt(i+j);
                j++;
            }
            System.out.println(w);
        }
        
    }
    //fucntions
    //fucntions
    //fucntions
    //fucntions
    static int[] input(int A[]) //input of Int Array
    {
        FastReader in=new FastReader();
        int N=A.length;
        for(int i=0; i<N; i++)
        {
            A[i]=in.nextInt();
        }
        return A;
    }

    static long[] input(long A[]) //Input of long Array
    {
        FastReader in=new FastReader();
        for(int i=0; i<A.length; i++)A[i]=in.nextLong();
        return A;
    }

    static int GCD(int a,int b) //wrong output if a ||b are intially zero
    {
        if(b==0)
        {
            return a;
        }
        else return GCD(b,a%b );
    }

    static boolean isPrime(int N)
    {
        for(int i=2; i*i<N; i++)
            if(N%i==0)return false;
        return true;
    }

}
//Code For FastReader
//Code For FastReader
//Code For FastReader
//Code For FastReader
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 (IOException e)
        {
            e.printStackTrace();
        }
        return str;
    }

}
//code For Reader CLass
/*
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(); 
} 
} 
 */

