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. 
#include <bits/stdc++.h>
using namespace std;
long long int mpow(long long int base, long long int exp) {
  base %= (long long)1e9 + 7;
  long long int result = 1ll;
  while (exp > 0) {
    if (exp & 1ll) result = ((long long)result * base) % (long long)1e9 + 7;
    base = ((long long)base * base) % (long long)1e9 + 7;
    exp >>= 1;
  }
  return result;
}
string sconvert(long long int n) {
  stringstream ss;
  ss << n;
  string str = ss.str();
  return str;
}
bool sortbysec(const pair<int, int> &a, const pair<int, int> &b) {
  return (a.second > b.second);
}
template <typename KeyType, typename ValueType>
std::pair<KeyType, ValueType> get_max(const std::map<KeyType, ValueType> &x) {
  using pairtype = std::pair<KeyType, ValueType>;
  return *std::max_element(x.begin(), x.end(),
                           [](const pairtype &p1, const pairtype &p2) {
                             return p1.second < p2.second;
                           });
}
long long int add(long long int a, long long int b,
                  long long int mod = (long long)1e9 + 7) {
  if (a + b >= mod) {
    return a + b - mod;
  }
  return a + b;
}
long long int sub(long long int a, long long int b,
                  long long int mod = (long long)1e9 + 7) {
  if (a - b < 0) {
    return a - b + mod;
  }
  return a - b;
}
long long int mul(long long int a, long long int b,
                  long long int mod = (long long)1e9 + 7) {
  return (long long int)(1ll * a * b % mod);
}
void single() {
  int n;
  cin >> n;
  string str;
  cin >> str;
  int x = str.length();
  for (int i = 0; i < 2 * n - 1; i += 2) {
    cout << str[i];
  }
  cout << '\n';
  return;
}
void multiple() {
  int asdf;
  cin >> asdf;
  while (asdf--) {
    single();
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(0);
  ;
  multiple();
}
