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. 

import java.util.*;
import java.io.*;
import java.math.*;

public class A {
    public static void main(String[] args) throws IOException {
        PrintWriter out = new PrintWriter(System.out);
        Reader s = new Reader();
        int t = s.i();
        while (t-- > 0) {
            int n = s.i();
            String str = s.s();
            char c = str.charAt(n-1);
            for (int i=0;i<n;i++) out.print(c);
            out.println();
        }
        out.flush();
    }

    private static int power(int a, int n) {
        int result = 1;
        while (n > 0) {
            if (n % 2 == 0) {
                a = (a * a);
                n /= 2;
            } else {
                result = (result * a);
                n--;
            }
        }
        return result;
    }

    private static int power(int a, int n, int p) {
        int result = 1;
        while (n > 0) {
            if (n % 2 == 0) {
                a = (a * a) % p;
                n /= 2;
            } else {
                result = (result * a) % p;
                n--;
            }
        }
        return result;
    }

    static class Reader {
        private InputStream mIs;
        private byte[] buf = new byte[1024];
        private int curChar, numChars;

        public Reader() {
            this(System.in);
        }

        public Reader(InputStream is) {
            mIs = is;
        }

        public int read() {
            if (numChars == -1) throw new InputMismatchException();
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = mIs.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0) return -1;
            }
            return buf[curChar++];
        }

        public String nextLine() {
            int c = read();
            while (isSpaceChar(c)) c = read();
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isEndOfLine(c));
            return res.toString();
        }

        public String s() {
            int c = read();
            while (isSpaceChar(c)) c = read();
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public long l() {
            int c = read();
            while (isSpaceChar(c)) c = read();
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            long res = 0;
            do {
                if (c < '0' || c > '9') throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public int i() {
            int c = read();
            while (isSpaceChar(c)) c = read();
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            int res = 0;
            do {
                if (c < '0' || c > '9') throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public double d() throws IOException {
            return Double.parseDouble(s());
        }

        public boolean isSpaceChar(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public boolean isEndOfLine(int c) {
            return c == '\n' || c == '\r' || c == -1;
        }

        public int[] arr(int n) {
            int[] ret = new int[n];
            for (int i = 0; i < n; i++) {
                ret[i] = i();
            }
            return ret;
        }

        public long[] arrLong(int n) {
            long[] ret = new long[n];
            for (int i = 0; i < n; i++) {
                ret[i] = l();
            }
            return ret;
        }
    }
//    static class pairLong implements Comparator<pairLong> {
//        long first, second;
//
//        pairLong() {
//        }
//
//        pairLong(long first, long second) {
//            this.first = first;
//            this.second = second;
//        }
//
//        @Override
//        public int compare(pairLong p1, pairLong p2) {
//            if (p1.first == p2.first) {
//                if(p1.second > p2.second) return 1;
//                else return -1;
//            }
//            if(p1.first > p2.first) return 1;
//            else return -1;
//        }
//    }
//    static class pair implements Comparator<pair> {
//        int first, second;
//
//        pair() {
//        }
//
//        pair(int first, int second) {
//            this.first = first;
//            this.second = second;
//        }
//
//        @Override
//        public int compare(pair p1, pair p2) {
//            if (p1.first == p2.first) return p1.second - p2.second;
//            return p1.first - p2.first;
//        }
//    }
}
