human
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. 
"""
P
assistant
#Here is Python program to print the corresponding binary string w of length n.
roblem link: 
Solution By Keshav Mishra 
"""
from sys import stdin,stdout
from collections import Counter , deque
from queue import PriorityQueue
import math

helperConstants = True 
helperUtilityFunctions = True 

def input(): return stdin.readline().strip()
# def print(s): stdout.write(str(s)+'\n')
if helperConstants:
    YES = 'YES'
    NO = 'NO'
    yes = 'yes'
    no = 'no'
    true = 'true'
    false = 'false'
    FALSE = 'FALSE'
    TRUE = 'TRUE'
    IMPOSSIBLE = 'IMPOSSIBLE'
    POSSIBLE = 'POSSIBLE'
    INF = float('inf')

if helperUtilityFunctions:
    # Input utility functions
    def getInputArray():
        return list(map(int, input().split()))
    def getIntegerInputs():
        return map(int, input().split())
    def getInputIntegerMatrix(n):
        matrix = []
        for i in range(n):
            matrix.append(list(map(int,input().split())))
        return matrix
    def getInputStringMatrix(n):
        matrix = []
        for i in range(n):
            matrix.append(input())
        return matrix

    # Output Utility functions
    def outputIntegerMatrix(matrix):
        for i in range(len(matrix)):
            print(*matrix[i])
    def outputStringMatrix(matrix):
        for i in range(len(matrix)):
            print(matrix[i])
    def kickstartoutput(testcase,*outputs):
        print('Case #%d:'%(testcase), *outputs)
    
    

def solve(t):
    n = int(input())
    s = input()
    char = s[n-1]
    print(char*(n))
    

if __name__ == '__main__':
    for t in range(int(input())):
        solve(t+1)