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.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;
import java.lang.*;
public class MAin{
	static int mod = 1000000007;
	static InputReader in = new InputReader(System.in);
	static PrintWriter pw = new PrintWriter(System.out);
	public static void main(String[] args) throws Exception {
		int t=in.readInt();
		while(t-->0){
			int n=in.readInt();
			String s=in.readString();
			String ans="";
			for(int i=0;i<=2*n-1;i+=2) {
				ans+=s.charAt(i);
			}
			System.out.println(ans);
		}
	}
	static String conc(int n) {
		String[] s=new String[n+1];
		s[4]="aabb";
		if(n==4)
			return s[4];
		if(s[n/2]==null) {
			s[n/2]=conc(n/2);
		}
		return s[n/2]+s[n/2];
	}
	static String  sort(String s1) {
		String s2="";
		int n1=s1.length();
		int[] a=new int[n1];
		for(int i=0;i<n1;i++){
			a[i]=s1.charAt(i);
		}
		Arrays.sort(a);
		for(int i=0;i<n1;i++) {
			s2+=(char)a[i];
		}
		return s2;
	}
	static boolean isVowel(char c) {
		if(c=='a'||c=='e'||c=='i'||c=='o'||c=='u')
			return true;
		return false;
	}
	static String removeChar(String s,int a,int b) {
		return s.substring(0,a)+s.substring(b,s.length());
	}
	static int[]  nextIntArray(int n){
		int[] arr= new int[n];
		int i=0;
		while(i<n){
			arr[i++]=in.readInt();
		}
		return arr;
	}
	static long[] nextLongArray(int n){
		long[]arr= new long[n];
		int i=0;
		while(i<n){
			arr[i++]=in.readLong();
		}
		return arr;
	}	
	static int[]  nextIntArray1(int n) {
		int[] arr= new int[n+1]; 
		int i=1;
		while(i<=n){
			arr[i++]=in.readInt();
		}
		return arr;
	}	    	
	static long[] nextLongArray1(int n){
		long[]arr= new long[n+1];
		int i=1;
		while(i<=n) {
			arr[i++]=in.readLong();
		}
		return arr;
	}	  
	static long gcd(long x, long y) {
		if (x % y == 0)
			return y;
		else
			return gcd(y, x % y);
	}
	static long pow(long n, long m) {
		if(m==0)
			return 1;
		else if(m==1)
			return n;
		else {
			long r=pow(n,m/2);
			if(m%2==0)
				return r*r;
			else
				return r*r*n;
		}
	}
	static long max(long a,long b,long c) {
		return Math.max(Math.max(a, b),c);
	}
	static long min(long a,long b,long c) {
		return Math.min(Math.min(a, b), c);
	}
	static class Pair implements Comparable<Pair> {
		int a, b;
		Pair(int a, int b) {
			this.a = a;
			this.b = b;
		}
		public int compareTo(Pair o) {
			if (this.a != o.a)
				return Integer.compare(this.a, o.a);
			else
				return Integer.compare(this.b, o.b);
			// return 0;
		}
		public boolean equals(Object o) {
			if (o instanceof Pair) {
				Pair p = (Pair) o;
				return p.a == a && p.b == b;
			}
			return false;
		}
		public int hashCode() {
			return new Integer(a).hashCode() * 31 + new Integer(b).hashCode();
		}
	}
	static class InputReader {
		private InputStream stream;
		private byte[] buf = new byte[1024];
		private int curChar;
		private int numChars;
		private SpaceCharFilter filter;
		public InputReader(InputStream stream) {
			this.stream = stream;
		}
		public int read() {
			if (numChars == -1)
				throw new InputMismatchException();
			if (curChar >= numChars) {
				curChar = 0;
				try {
					numChars = stream.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (numChars <= 0)
					return -1;
			}
			return buf[curChar++];
		}
		public int readInt() {
			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 String readString() {
			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 double readDouble() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			double res = 0;
			while (!isSpaceChar(c) && c != '.') {
				if (c == 'e' || c == 'E')
					return res * Math.pow(10, readInt());
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			}
			if (c == '.') {
				c = read();
				double m = 1;
				while (!isSpaceChar(c)) {
					if (c == 'e' || c == 'E')
						return res * Math.pow(10, readInt());
					if (c < '0' || c > '9')
						throw new InputMismatchException();
					m /= 10;
					res += (c - '0') * m;
					c = read();
				}
			}
			return res * sgn;
		}
		public long readLong() {
			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 boolean isSpaceChar(int c) {
			if (filter != null)
				return filter.isSpaceChar(c);
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}
		public interface SpaceCharFilter {
			public boolean isSpaceChar(int ch);
		}
	}
}


