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 sys, os, io
def rs(): return sys.stdin.readline().rstrip()
def ri(): return int(sys.stdin.readline())
def ria(): return list(map(int, sys.stdin.readline().split()))
def ws(s): sys.stdout.write(s + '\n')
def wi(n): sys.stdout.write(str(n) + '\n')
def wia(a): sys.stdout.write(' '.join([str(x) for x in a]) + '\n')
import math,datetime,functools,itertools,operator,bisect,fractions
from collections import deque,defaultdict,OrderedDict
from fractions import Fraction
from decimal import Decimal
    
def main():
    starttime=datetime.datetime.now()
    if(os.path.exists('input.txt')):
        sys.stdin = open("input.txt","r")
        sys.stdout = open("output.txt","w")

    for _ in range(ri()):
        n=ri()
        s=rs()
        z=""
        for i in range(0,len(s),2):
            z+=s[i]
        print(z)
        
                    
            
        

                
        
            
            
        
        
                
                

        
            
            
        
            
        
        
        
        
                

        

                
            
             
            
            
        

        
        
        
            
            
            
                
        
                
        
            
        
              
        
                
            
                
                
                
        
            
        
        
                    
            
            
        
        
        
        
        
            
                
                
            
            
            
            
        


                
            
            

                    
        
        
                
        
        
                
                    
        
        
        
        
        
        
        
       
  
            
            

            
                
                
        
        
            
                    
            
            

        
        

    
                
                    
                
                
                
                    
                
        
        
        
        
        
        
        
            
            
        
        
        
            
        
                
        
        
            
            
        
        
                    
                    
        
        

                
                    
        
            
            
                
        
        
           
            
            
            

        
        
        


            
            
            
           
            
            
            
            
        
            
                
            
            
                            
                
            
            
        
            
            
            
            
            
            
        
        
                
                
                
                  
                    
                    
                
            
        
        
                
                
            
        
        
                    
                    
                    
            
            
            
            
            
        

                    
                    
          
        
        
        
            
            
                
                    
            
        
        
                
                    
                    
                    
            

        
            
            

            

                
                
                
                
            
        

        
        
            
            
                
                
        
        
        
                
            
        
        
        
        
        
            
            
        
                
                
                

        

                    
                
            

        
        
            
            
            
                
                
            
                
                
        

                
        
        

        
            
                
                
            
        
            
            
                
                

    

            
        
        
       
                
                    
                
            
            
        

            
            
                
            
            
        
                
        
                
                
            
        
            
                
                
                    
                
                
        
        


        
        
        
        

            
                    
            
                    
        
 

                
        
        

            
        
        
                
            
                
     
        
        
                
                
        
        
        
        
                
        

            
                
            


        
                
            
            
            
            
                    
        















    #<--Solving Area Ends
    endtime=datetime.datetime.now()
    time=(endtime-starttime).total_seconds()*1000
    if(os.path.exists('input.txt')):
        print("Time:",time,"ms")  
    
                
class FastReader(io.IOBase):
    newlines = 0

    def __init__(self, fd, chunk_size=1024 * 8):
        self._fd = fd
        self._chunk_size = chunk_size
        self.buffer = io.BytesIO()

    def read(self):
        while True:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, self._chunk_size))
            if not b:
                break
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines = 0
        return self.buffer.read()

    def readline(self, size=-1):
        while self.newlines == 0:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, self._chunk_size if size == -1 else size))
            self.newlines = b.count(b"\n") + (not b)
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines -= 1
        return self.buffer.readline()


class FastWriter(io.IOBase):

    def __init__(self, fd):
        self._fd = fd
        self.buffer = io.BytesIO()
        self.write = self.buffer.write

    def flush(self):
        os.write(self._fd, self.buffer.getvalue())
        self.buffer.truncate(0), self.buffer.seek(0)


class FastStdin(io.IOBase):
    def __init__(self, fd=0):
        self.buffer = FastReader(fd)
        self.read = lambda: self.buffer.read().decode("ascii")
        self.readline = lambda: self.buffer.readline().decode("ascii")


class FastStdout(io.IOBase):
    def __init__(self, fd=1):
        self.buffer = FastWriter(fd)
        self.write = lambda s: self.buffer.write(s.encode("ascii"))
        self.flush = self.buffer.flush


if __name__ == '__main__':
    sys.stdin = FastStdin()
    sys.stdout = FastStdout()
    main()







