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 com.company;

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

import static java.lang.Math.*;

//public class StringSimilarity {
        public class Main {

    public static void main(String[] args) throws IOException {
        int t = sc.nextInt();
        for (int i = 0; i < t; i++) {
            int n = sc.nextInt();
            boolean[] arr = new boolean[n];
            Arrays.fill(arr, true);
            String str = sc.nextString();
            for (int j = 0; j < n; j++) {
                String temp = str.substring(j, n + j);
//                out.println(temp + "");
                for (int k = 0; k < n; k++) {
                    arr[k] &= temp.charAt(k) == '1';
                }
            }
            StringBuilder st=new StringBuilder();
            for (int j = 0; j < arr.length; j++) {
                st.append(arr[j]?'1':'0');
            }
            out.println(st.toString()+"");
        }

        close.close();
    }






















    /* This is O(scary), but seems quick enough in practice. */

    static void debug(Object... obj) {
        System.err.println(Arrays.deepToString(obj).replace("], ", "]\n"));
    }

    static void debugV2(Object... obj) {
        System.out.println(Arrays.deepToString(obj)
                .replace("],", "\n").replace(",", "\t")
                .replaceAll("[\\[\\]]", " "));
    }

    static class Sc {
        final private int BUFFER_SIZE = 1 << 16;
        private final DataInputStream din;
        private final byte[] buffer;
        private int bufferPointer, bytesRead;

        public Sc() {
            din = new DataInputStream(System.in);
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }

        public Sc(String file_name) throws IOException {
            din = new DataInputStream(new FileInputStream(file_name));
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }

        public String readLine() throws IOException {
            byte[] buf = new byte[64]; // line length
            int cnt = 0, c;
            while ((c = read()) != -1) {
                if (c == '\n')
                    break;
                buf[cnt++] = (byte) c;
            }
            return new String(buf, 0, cnt);
        }

        public String nextString() throws IOException {
            StringBuilder sb = new StringBuilder();
            int n = read();
            while (isWhiteSpace(n))
                n = read();
            while (!isWhiteSpace(n)) {
                sb.append((char) n);
                n = read();
            }
            return sb.toString();
        }

        private boolean isWhiteSpace(int n) {
            return n == ' ' || n == '\n' || n == '\r' || n == '\t' || n == -1;
        }

        public int nextInt() throws IOException {
            int ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();
            do {
                ret = ret * 10 + c - '0';
            } while ((c = read()) >= '0' && c <= '9');

            if (neg)
                return -ret;
            return ret;
        }

        public long nextLong() throws IOException {
            long ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();
            do {
                ret = ret * 10 + c - '0';
            }
            while ((c = read()) >= '0' && c <= '9');
            if (neg)
                return -ret;
            return ret;
        }

        public double nextDouble() throws IOException {
            double ret = 0, div = 1;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();

            do {
                ret = ret * 10 + c - '0';
            }
            while ((c = read()) >= '0' && c <= '9');

            if (c == '.') {
                while ((c = read()) >= '0' && c <= '9') {
                    ret += (c - '0') / (div *= 10);
                }
            }

            if (neg)
                return -ret;
            return ret;
        }

        private void fillBuffer() throws IOException {
            bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
            if (bytesRead == -1)
                buffer[0] = -1;
        }

        private byte read() throws IOException {
            if (bufferPointer == bytesRead)
                fillBuffer();
            return buffer[bufferPointer++];
        }

        public void close() throws IOException {
            if (din == null)
                return;
            din.close();
        }
    }


    static class Print {
        private final OutputStream out;

        public Print() {
            this.out = System.out;
        }

        public void print(String str) throws IOException {
            for (int i = 0; i < str.length(); i++) {
                out.write(str.charAt(i));
            }
        }

        public void println(String str) throws IOException {
            print(str);
            out.write('\n');
        }

        public void close() throws IOException {
            out.close();
        }
    }

    static Sc sc = new Sc();
    static Print out = new Print();
    static BufferedWriter close = new BufferedWriter(new OutputStreamWriter(System.out));
    // 10:24 PM Mon 03 2021 3/22/2021
}