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

public class EDU94A {
	static PrintWriter pw;

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

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

		public FastReader(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 next() {
			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(next());
		}

		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 void scanIntArr(int[] arr) {
			for (int li = 0; li < arr.length; ++li)
				arr[li] = i();
		}

		public void scanIntIndexArr(int[] arr) {
			for (int li = 0; li < arr.length; ++li) {
				arr[li] = i() - 1;
			}
		}

		public void printIntArr(int[] arr) {
			for (int li = 0; li < arr.length; ++li)
				pw.print(arr[li] + " ");
			pw.println();
		}

		public void printLongArr(long[] arr) {
			for (int li = 0; li < arr.length; ++li)
				pw.print(arr[li] + " ");
			pw.println();
		}

		public void scanLongArr(long[] arr) {
			for (int i = 0; i < arr.length; ++i) {
				arr[i] = l();
			}
		}

		public void shuffle(int[] arr) {
			for (int i = arr.length; i > 0; --i) {
				int r = (int) (Math.random() * i);
				int temp = arr[i - 1];
				arr[i - 1] = arr[r];
				arr[r] = temp;
			}
		}

		public int findMax(int[] arr) {
			return Arrays.stream(arr).max().getAsInt();
		}
	}

	public static void main(String[] args) throws IOException {
		FastReader fr = new FastReader();
		pw = new PrintWriter(System.out);
		int i, j, n, m, temp, t;
		String s;
		StringBuilder s1;
		t = fr.i();
		while (t-- > 0) {
			n = fr.i();
			s = fr.nextLine();
			s1 = new StringBuilder();
			for (i = 0; i < n; i++) {
				s1.append(s.charAt(n - 1));
			}
			pw.println(s1.toString());
		}
		pw.flush();
		pw.close();
	}
}