description: Mocha is a young girl from high school. She has learned so much interesting knowledge from her teachers, especially her math teacher. Recently, Mocha is learning about binary system and very interested in bitwise operation.
  
  This day, Mocha got a sequence a of length n. In each operation, she can select an arbitrary interval [l, r] and for all values i (0≤ i ≤ r-l), replace a_{l+i} with a_{l+i}  \&  a_{r-i} at the same time, where \& denotes the [bitwise AND operation](https://en.wikipedia.org/wiki/Bitwise_operation#AND). This operation can be performed any number of times.
  
  For example, if n=5, the array is [a_1,a_2,a_3,a_4,a_5], and Mocha selects the interval [2,5], then the new array is [a_1,a_2 \&  a_5, a_3 \&  a_4, a_4 \&  a_3, a_5 \&  a_2].
  
  Now Mocha wants to minimize the maximum value in the sequence. As her best friend, can you help her to get the answer?
  
  Input
  
  Each test contains multiple test cases. 
  
  The first line contains a single integer t (1 ≤ t ≤ 100) — the number of test cases. Each test case consists of two lines.
  
  The first line of each test case contains a single integer n (1 ≤ n ≤ 100) — the length of the sequence.
  
  The second line of each test case contains n integers a_1, a_2, …, a_n (0 ≤ a_i ≤ 10^9).
  
  Output
  
  For each test case, print one integer — the minimal value of the maximum value in the sequence.
  
  Example
  
  Input
  
  
  4
  2
  1 2
  3
  1 1 3
  4
  3 11 3 7
  5
  11 7 15 3 7
  
  
  Output
  
  
  0
  1
  3
  3
  
  Note
  
  In the first test case, Mocha can choose the interval [1,2], then the sequence becomes [ 0, 0], where the first element is 1 \& 2, and the second element is 2 \& 1.
  
  In the second test case, Mocha can choose the interval [1,3], then the sequence becomes [ 1,1,1], where the first element is 1 \& 3, the second element is 1 \& 1, and the third element is 3 \& 1.
solution: 	import java.io.BufferedReader;
  	import java.io.IOException;
  	import java.io.InputStreamReader;
  	import java.util.ArrayList;
  	import java.util.Arrays;
  	import java.util.Random;
  	import java.util.StringTokenizer;
  	public class A{
  	// author: Tarun Verma
  	static FastScanner sc = new FastScanner();
  	static int inf = Integer.MAX_VALUE;
  	static long mod = 1000000007;
  	
  	public static void solve() {
  		int n = sc.nextInt();
  		int arr[] = sc.readArray(n);
  		int ans = arr[0];
  		for(int i = 1;i<n;i++) {
  			ans = ans & arr[i];
  		}
  		System.out.println(ans);
  	}
  	
  	public static void main(String[] args) {
  		int t = 1;
  		t = sc.nextInt();
  		outer: for (int tt = 0; tt < t; tt++) {
  			solve();
  		}
  	}
  	/* Common Mistakes By Me
  	 * make sure to read the bottom part of question
  	 * special cases (n=1?)
  	 * In Game Theory Check your solution and consider all the solutions
  	 * Always initialise value to the declare array in local scope
  	 * don't use debugs in interactive problems
  	 * Always Reset vis,adj array upto n+1 otherwise can cause TLE
  	*/
  	////////////////////////////////////////////////////////////////////////////////////
  	////////////////////DO NOT BELOW BEFORE THIS LINE //////////////////////////////////
  	////////////////////////////////////////////////////////////////////////////////////
  	
  	static boolean isPalindrom(char[] arr, int i, int j) {
  		boolean ok = true;
  		while (i <= j) {
  			if (arr[i] != arr[j]) {
  				ok = false;
  				break;
  			}
  			i++;
  			j--;
  		}
  		return ok;
  	}
  	
  	static int max(int a, int b) {
  		return Math.max(a, b);
  	}
  	
  	static int min(int a, int b) {
  		return Math.min(a, b);
  	}
  	
  	static long max(long a, long b) {
  		return Math.max(a, b);
  	}
  	
  	static long min(long a, long b) {
  		return Math.min(a, b);
  	}
  	
  	static int abs(int a) {
  		return Math.abs(a);
  	}
  	
  	static long abs(long a) {
  		return Math.abs(a);
  	}
  	
  	static void swap(long arr[], int i, int j) {
  		long temp = arr[i];
  		arr[i] = arr[j];
  		arr[j] = temp;
  	}
  	
  	static void swap(int arr[], int i, int j) {
  		int temp = arr[i];
  		arr[i] = arr[j];
  		arr[j] = temp;
  	}
  	
  	static int maxArr(int arr[]) {
  		int maxi = Integer.MIN_VALUE;
  		for (int x : arr)
  			maxi = max(maxi, x);
  		return maxi;
  	}
  	
  	static int minArr(int arr[]) {
  		int mini = Integer.MAX_VALUE;
  		for (int x : arr)
  			mini = min(mini, x);
  		return mini;
  	}
  	
  	static long maxArr(long arr[]) {
  		long maxi = Long.MIN_VALUE;
  		for (long x : arr)
  			maxi = max(maxi, x);
  		return maxi;
  	}
  	
  	static long minArr(long arr[]) {
  		long mini = Long.MAX_VALUE;
  		for (long x : arr)
  			mini = min(mini, x);
  		return mini;
  	}
  	
  	static int gcd(int a, int b) {
  		if (b == 0)
  			return a;
  		return gcd(b, a % b);
  	}
  	
  	static long gcd(long a, long b) {
  		if (b == 0)
  			return a;
  		return gcd(b, a % b);
  	}
  	
  	static void ruffleSort(int[] a) {
  		int n = a.length;
  		Random r = new Random();
  		for (int i = 0; i < a.length; i++) {
  			int oi = r.nextInt(n);
  			int temp = a[i];
  			a[i] = a[oi];
  			a[oi] = temp;
  		}
  		Arrays.sort(a);
  	}
  	
  	public static int binarySearch(int a[], int target) {
  		int left = 0;
  		int right = a.length - 1;
  		int mid = (left + right) / 2;
  		int i = 0;
  		while (left <= right) {
  			if (a[mid] <= target) {
  				i = mid + 1;
  				left = mid + 1;
  			} else {
  				right = mid - 1;
  			}
  			mid = (left + right) / 2;
  		}
  		return i;
  	}
  	
  	static class FastScanner {
  		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
  		StringTokenizer st = new StringTokenizer("");
  	
  		String next() {
  			while (!st.hasMoreTokens())
  				try {
  					st = new StringTokenizer(br.readLine());
  				} catch (IOException e) {
  					e.printStackTrace();
  				}
  			return st.nextToken();
  		}
  	
  		int nextInt() {
  			return Integer.parseInt(next());
  		}
  	
  		int[] readArray(int n) {
  			int[] a = new int[n];
  			for (int i = 0; i < n; i++)
  				a[i] = nextInt();
  			return a;
  		}
  	
  		int[][] read2dArray(int n, int m) {
  			int arr[][] = new int[n][m];
  			for (int i = 0; i < n; i++) {
  				for (int j = 0; j < m; j++) {
  					arr[i][j] = nextInt();
  				}
  			}
  			return arr;
  		}
  	
  		ArrayList<Integer> readArrayList(int n) {
  			ArrayList<Integer> arr = new ArrayList<Integer>();
  			for (int i = 0; i < n; i++) {
  				int a = nextInt();
  				arr.add(a);
  			}
  			return arr;
  		}
  	
  		long nextLong() {
  			return Long.parseLong(next());
  		}
  	}
  	
  	static class pair {
  		int fr, sc;
  	
  		pair(int fr, int sc) {
  			this.fr = fr;
  			this.sc = sc;
  		}
  	}
  	
  	////////////////////////////////////////////////////////////////////////////////////	
  	
  	}