Lee was cleaning his house for the party when he found a messy string under the carpets. Now he'd like to make it clean accurately and in a stylish way...

The string s he found is a binary string of length n (i. e. string consists only of 0-s and 1-s).

In one move he can choose two consecutive characters s_i and s_{i+1}, and if s_i is 1 and s_{i + 1} is 0, he can erase exactly one of them (he can choose which one to erase but he can't erase both characters simultaneously). The string shrinks after erasing.

Lee can make an arbitrary number of moves (possibly zero) and he'd like to make the string s as clean as possible. He thinks for two different strings x and y, the shorter string is cleaner, and if they are the same length, then the lexicographically smaller string is cleaner.

Now you should answer t test cases: for the i-th test case, print the cleanest possible string that Lee can get by doing some number of moves.

Small reminder: if we have two strings x and y of the same length then x is lexicographically smaller than y if there is a position i such that x_1 = y_1, x_2 = y_2,..., x_{i - 1} = y_{i - 1} and x_i < y_i.

Input

The first line contains the integer t (1 ≤ t ≤ 10^4) — the number of test cases. 

Next 2t lines contain test cases — one per two lines.

The first line of each test case contains the integer n (1 ≤ n ≤ 10^5) — the length of the string s.

The second line contains the binary string s. The string s is a string of length n which consists only of zeroes and ones.

It's guaranteed that sum of n over test cases doesn't exceed 10^5.

Output

Print t answers — one per test case.

The answer to the i-th test case is the cleanest string Lee can get after doing some number of moves (possibly zero).

Example

Input


5
10
0001111111
4
0101
8
11001101
10
1110000000
1
1


Output


0001111111
001
01
0
1

Note

In the first test case, Lee can't perform any moves.

In the second test case, Lee should erase s_2.

In the third test case, Lee can make moves, for example, in the following order: 11001101 → 1100101 → 110101 → 10101 → 1101 → 101 → 01.
// package name;
import java.io.*;
import java.util.*;

public class Main {
	static final long mod = 998244353;
	static final long lmx = 9223372036854775807l, lmn = -9223372036854775808l;
	static final int imx = 2147483647, imn = -2147483648;
	static final String Y = "YES", NO = "NO", LN = "\n", SPC = " ";
	static Scanner s = new Scanner(System.in);
	//static Reader s = new Reader();
	static PrintWriter out = new PrintWriter(System.out);
	static StringBuffer sb = new StringBuffer();

	public static void main(String[] args) throws IOException {
		int t = 1;
		t = s.nextInt();
		//slinp();
		while (t > 0) {
			t--;
			int n = iinp();
			slinp();
			String st = slinp();
			int i = 0;
			int l = st.length();
			char c = st.charAt(i);
			int z = 0;
			while(i < l && c == '0') {
				app(c + "");
				z++; i++;
				if(i < l) c = st.charAt(i);
			}
			
			i = l - 1;
			c = st.charAt(i);
			int x = 0;
			while(i >= z && c == '1') {
				//app(c + "");
				x++;
				i--;
				if(i >= 0) c = st.charAt(i);
			}
			if(z + x != l) {
				app("0");
			}
			while(x-- > 0) {
				app("1");
			}
			ln();
		}
		out.print(sb);
		out.flush();
	}
	static int res = Integer.MAX_VALUE;
	static boolean fun(int a[], int mid, int ev, int k) {
		int n = a.length;
		int ans = 0;
		int z = 1;
		for(int i = 0; i < n; i++) {
			if(z > k) break;
			if(z % 2 == ev) {
				z++;
			}
			else {
				if(a[i] <= mid) {
					z++;
					ans = max(ans, a[i]);
				}
			}
		}
		if(z == k + 1) {
			res = min(res, ans);
			return true;
		}
		return false;
	}
	
	static void app(String x) throws IOException {
		sb.append(x);
	}

	static void spc() throws IOException {
		sb.append(SPC);
	}

	static void ln() throws IOException {
		sb.append(LN);
	}

	static int iinp() throws IOException {
		return s.nextInt();
	}

	static long linp() throws IOException {
		return s.nextLong();
	}

	static double dinp() throws IOException {
		return s.nextDouble();
	}

	static String sinp() throws IOException {
		return s.next();
	}

	static String slinp() throws IOException {
		return s.nextLine();
	}

	static int[] iarr(int n) {
		return new int[n];
	}

	static long[] larr(int n) {
		return new long[n];
	}

	static double[] darr(int n) {
		return new double[n];
	}

	static boolean[] barr(int n) {
		return new boolean[n];
	}

	static String[] sarr(int n) {
		return new String[n];
	}

	static int[][] iarr(int n, int m) {
		return new int[n][m];
	}

	static long[][] larr(int n, int m) {
		return new long[n][m];
	}

	static int[] iinp(int n, int st, int size) throws IOException {
		int a[] = iarr(n);
		for (int i = st; i < st + size; i++)
			a[i] = iinp();
		return a;
	}

	static long[] linp(int n, int st, int size) throws IOException {
		long a[] = larr(n);
		for (int i = st; i < st + size; i++)
			a[i] = linp();
		return a;
	}

	static String[] sinp(int n, int st, int size, String str) throws IOException {
		String a[] = sarr(n);
		for (int i = st; i < st + size; i++)
			if (str.equalsIgnoreCase(SPC))
				a[i] = sinp();
			else
				a[i] = slinp();
		return a;
	}

	static int[][] iinp(int n, int m, int row, int rows, int col, int cols) throws IOException {
		int a[][] = iarr(n, m);
		for (int i = row; i < row + rows; i++)
			for (int j = col; j < col + cols; j++)
				a[i][j] = iinp();
		return a;
	}

	static long[][] linp(int n, int m, int row, int rows, int col, int cols) throws IOException {
		long a[][] = larr(n, m);
		for (int i = row; i < row + rows; i++)
			for (int j = col; j < col + cols; j++)
				a[i][j] = linp();
		return a;
	}

	static void ginp(ArrayList<Integer> g[], int m) throws IOException {
		for (int i = 0; i < m; i++) {
			int u = iinp(), v = iinp();
			g[u].add(u);
			g[v].add(u);
		}
	}

	static long min(long... a) {
		long min = lmx;//Long.MAX_VALUE;
		for (long i : a)
			if (i < min)
				min = i;
		return min;
	}

	static int min(int... a) {
		int min = imx;//Long.MAX_VALUE;
		for (int i : a)
			if (i < min)
				min = i;
		return min;
	}

	static long max(long... a) {
		long max = lmn;//Long.MIN_VALUE;
		for (long i : a)
			if (i > max)
				max = i;
		return max;
	}

	static int max(int... a) {
		int max = imn;//Long.MIN_VALUE;
		for (int i : a)
			if (i > max)
				max = i;
		return max;
	}

	static long gcd(long a, long b) {
		if (b == 0)
			return a;
		return gcd(b, a % b);
	}

	static int gcd(int a, int b) {
		if (b == 0)
			return a;
		return gcd(b, a % b);
	}

	static void sort(int a[]) {
		Arrays.sort(a);
	};

	static void sort(long a[]) {
		Arrays.sort(a);
	};

	static void sort(String a[]) {
		Arrays.sort(a);
	};

	static void sort(int a[], int st, int e) {
		Arrays.sort(a, st, e);
	};

	static void sort(long a[], int st, int e) {
		Arrays.sort(a, st, e);
	};

	static void sort(String a[], int st, int e) {
		Arrays.sort(a, st, e);
	};

	static void sortbycol(int arr[][]) {
		Arrays.sort(arr, new Comparator<int[]>() {
			public int compare(int[] x, int[] y) {
				if (x[1] == y[1])
					return x[2] - y[2];
				return x[1] - y[1]; // sort in increasing order on the basis of first column
			}
		});
	}

	static StringBuffer printarr(long a[], String str) {
		StringBuffer ans = new StringBuffer();
		for (long i : a)
			ans.append(i + str);
		return ans;
	}

}

class Pair implements Comparator<Pair> {
	long a, b;

	Pair(long x, long y) {
		a = x;
		b = y;
	}

	public int compare(Pair p1, Pair p2) {
		if (p1.a != p2.a)
			return (p1.a - p2.a > 0) ? 1 : -1;
		return (p1.b - p2.b > 0) ? 1 : -1;
	}
}