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. 
//package MyPackage;
import java.io.*;
import java.util.*;
import java.text.*;
public class MyClass {
    final static long mod = 1_000_000_007;
    final static int mini = Integer.MIN_VALUE;
    final static int maxi = Integer.MAX_VALUE;
    static long gcd(long a, long b) {
        if (b == 0) return a;
        return gcd(b, a % b);
    }
    static long power(long a, long b) {
        long res = 1;
        while(b-- > 0) res = (res % mod * a % mod) % mod;
        return res;
    }
    static long ncr(long n, long r) {
        if (r > n - r) r = n - r;
        long[] C = new long[(int) r + 1];
        C[0] = 1;
        for (int i = 1; i <= n; i++) {
            for (long j = Math.min(i, r); j > 0; j--)
                C[(int) j] = (C[(int) j] + C[(int) j - 1]) % mod;
        }
        return C[(int) r];
    }
    static boolean isPrime(int n) {
        if (n <= 1)
            return false;
        else if (n == 2)
            return true;
        else if (n % 2 == 0)
            return false;
        for (int i = 3; i <= Math.sqrt(n); i += 2) {
            if (n % i == 0)
                return false;
        }
        return true;
    }
    static int countSetBits(int n) {
        int count = 0;
        while(n > 0) {
            n &= (n - 1);
            count++;
        }
        return count;
    }
    static int digits(long n) {
        int count = 0;
        long temp = n;
        while (temp > 0) {
            temp /= 10;
            count++;
        }
        return count;
    }
    static boolean isPalindrome(long i) {
        long originalNum = i;
        long remainder;
        long reversedNum = 0;
        while (i != 0) {
            remainder = i % 10;
            reversedNum = reversedNum * 10 + remainder;
            i /= 10;
        }
        return originalNum == reversedNum;
    }
    static long lcm(long a, long b) {
        return (a / gcd(a, b)) * b;
    }
    static void sort(long[] a) {
        ArrayList<Long> l = new ArrayList<>();
        for (long value : a) {
            l.add(value);
        }
        Collections.sort(l);
        for (int i = 0; i < l.size(); i++)
            a[i] = l.get(i);
    }
    static void sort(int[] a) {
        ArrayList<Integer> l = new ArrayList<>();
        for (int value : a) {
            l.add(value);
        }
        Collections.sort(l);
        for (int i = 0; i < l.size(); i++)
            a[i] = l.get(i);
    }
    static void reverse(int[] arr) {
        int l = 0;
        int h = arr.length - 1;
        while (l < h) {
            swap(arr, l, h);
            l++;
            h--;
        }
    }
    static String reverse(String s) {
        StringBuilder res = new StringBuilder(s);
        return res.reverse().toString();
    }
    static long fact(long n) {
        long res = 1, i;
        for (i = 2; i <= n; i++)
            res *= i;
        return res;
    }
    static void swap(int[] arr, int i, int j) {
        int temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
    }
    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        String n() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int nint() {
            return Integer.parseInt(n());
        }

        long nlong() {
            return Long.parseLong(n());
        }

        double ndouble() {
            return Double.parseDouble(n());
        }

        int[] narr(int n) {
            int[] a = new int[n];
            for (int i = 0; i < n; i++) a[i] = nint();
            return a;
        }

        int[][] narr(int n, int m) {
            int[][] a = new int[n][m];
            for (int i = 0; i < n; i++)
                for (int j = 0; j < m; j++)
                    a[i][j] = nint();
            return a;
        }

        String nline() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
    }
    public static class Pair {
        int a;
        int b;

        public Pair(int a, int b) {
            this.a = a;
            this.b = b;
        }
    }
    public static void main(String[] args) {
        FastReader sc = new FastReader();
        PrintWriter out = new PrintWriter(System.out);
        int t = sc.nint();
        while(t-- > 0) {
            int n = sc.nint();
            String s = sc.n();
            for(int i = 0; i < s.length(); i += 2) {
                out.print(s.charAt(i));
            }
            out.println();
        }
        out.flush();
        out.close();
    }
}