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. 
MOD = 1000000007
from collections import defaultdict as dd,Counter,deque

def si(): return input()
def ii(): return int(input())
def li(): return list(map(int,input().split()))
def mi(): return map(int,input().split())
def out(v): print(v)
def spout(): print(v,end=" ")
def d2b(n): return bin(n).replace("0b","")
def twod(n,m,num):return [[num for x in range(m)] for y in range(n)]
def vow(): return ['a','e','i','o','u']
def let(): return [chr(i) for i in range(97,123)]
def gcd(x, y):
    while y:
        x, y = y, x % y
    return x
def ispow2(x):
    return (x and (not(x & (x - 1))))
def prime_factors(n):
    i = 2
    factors = []
    while i * i <= n:
        if n % i: i+=1
        else:
            n //= i
            factors.append(i)
    if n > 1: factors.append(n)
    return (list(factors))
    
    
t=ii()
while t:
    t-=1
    n=ii()
    s=si()
    a=list(s[:n])
    for i in range(len(s)-n+1):
        f=0
        for j in range(n):
            if s[i+j]==a[j]:
                f=1
                break
        if f==0:
            a[0]=s[i]
    print("".join(a))