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. 
from 
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Can you provide a Python program to print the corresponding binary string w of length n?
assistant
#Here is Python program to print the corresponding binary string w of length n.
sys import stdin
from collections import deque
# https://codeforces.com/contest/1354/status/D
mod = 10**9 + 7
import sys
import random
sys.setrecursionlimit(10**6)
from queue import PriorityQueue
from collections import Counter as cc
# def rl():
#     return [int(w) for w in stdin.readline().split()]
from bisect import bisect_right
from bisect import bisect_left
from collections import defaultdict
from math import sqrt,factorial,gcd,log2,inf,ceil
# map(int,input().split())
# # l = list(map(int,input().split()))
# from itertools import permutations
import heapq
# input = lambda: sys.stdin.readline().rstrip()
# from sys import stdin
# input = lambda : sys.stdin.readline()
from collections import deque
# https://codeforces.com/contest/1354/status/D
mod = 10**9 + 7
import sys
import random
sys.setrecursionlimit(10**6)
from queue import PriorityQueue
from collections import Counter as cc
# def rl():
#     return [int(w) for w in stdin.readline().split()]
from bisect import bisect_right
from bisect import bisect_left
from collections import defaultdict
from math import sqrt,factorial,gcd,log2,inf,ceil
# map(int,input().split())
# # l = list(map(int,input().split()))
# from itertools import permutations
import heapq
# input = lambda: sys.stdin.readline().rstrip()
input = lambda : sys.stdin.readline().rstrip()
from sys import stdin, stdout
from heapq import heapify, heappush, heappop
from itertools import permutations
from math import factorial as f

    # def ncr(x, y):
    #     return f(x) // (f(y) * f(x - y))
def ncr(n, r, p):
    num = den = 1
    for i in range(r):
        num = (num * (n - i)) % p
        den = (den * (i + 1)) % p
    return (num * pow(den,
                      p - 2, p)) % p

import sys

# input = sys.stdin.readline
# LCA
# def bfs(na):
#
#     queue = [na]
#     boo[na] = True
#     level[na] = 0
#
#     while queue!=[]:
#
#         z = queue.pop(0)
#
#         for i in hash[z]:
#
#             if not boo[i]:
#
#                 queue.append(i)
#                 level[i] = level[z] + 1
#   ...