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.*;
  import java.util.*;
  //import java.math.*;  // for bigInteger
  
  public class Main {
  
    static InputReader sc;
    static PrintWriter out;
  
    public static void main(String args[]) throws Exception {
      sc = new InputReader();
      out = new PrintWriter(System.out);
      int t = 1;  
      t = sc.nI();
      for (int tt = 1; tt <= t; ++tt)
        solve(tt);
      out.close();
    }
  
    static void solve(int tn) {
      int n = sc.nI();
      int[] a = new int[n];
      for(int i=0;i<n;++i) a[i] = sc.nI();
      int ans = a[0];
      for(int i:a) ans&=i;
      out.println(ans);
    }
  
    public static class InputReader {
      BufferedReader br;
      StringTokenizer st;
  
      InputReader() {
        br = new BufferedReader(new InputStreamReader(System.in));
      }
  
      public int nI() {
        return Integer.parseInt(n());
      }
  
      public long nL() {
        return Long.parseLong(n());
      }
  
      public double nD() {
        return Double.parseDouble(n());
      }
  
      public String n() {
        while (st == null || !st.hasMoreTokens()) {
          try {
            st = new StringTokenizer(br.readLine());
          } catch (IOException e) {
          }
        }
        return st.nextToken();
      }
    }
  
    /*
     * private final static int m =(int)1e9+7; private static class Pair<T,V> { T
     * first; V second; Pair(final T first, final V second) { this.first = first;
     * this.second = second; } public boolean equals(Object o) { Pair given =
     * (Pair)o; if(given.first == first && given.second == second) return true;
     * return false; } public int hashCode() { long temp =
     * (long)(first.hashCode())*31; temp = (temp+(long)second.hashCode())%m; return
     * (int)temp; } }
     */
  
    public static void debug(final int[]... var) {
      for (final int[] row : var) {
        debug(row);
      }
    }
  
    public static void debug(final long[]... var) {
      for (final long[] row : var) {
        debug(row);
      }
    }
  
    public static void debug(final String[]... var) {
      for (final String[] row : var) {
        debug(row);
      }
    }
  
    public static void debug(final double[]... var) {
      for (final double[] row : var) {
        debug(row);
      }
    }
  
    public static void debug(final char[]... var) {
      for (final char[] row : var) {
        debug(row);
      }
    }
  
    public static void debug(final int... var) {
      for (final int i : var)
        System.err.print(i + " ");
      System.err.println();
    }
  
    public static void debug(final String... var) {
      for (final String i : var)
        System.err.print(i + " ");
      System.err.println();
    }
  
    public static void debug(final double... var) {
      for (final double i : var)
        System.err.print(i + " ");
      System.err.println();
    }
  
    public static void debug(final long... var) {
      for (final long i : var)
        System.err.print(i + " ");
      System.err.println();
    }
  
    public static void debug(final char... var) {
      for (final char c : var)
        System.err.print(c + " ");
      System.err.println();
    }
  
    /*
     * public static <T> void debug(T ...varargs) { // Warning // Heap Pollution
     * might occur // this overrides even 1d and 2d array methods as it is an
     * object... // + i am not using object based array like Integer[] // I am using
     * int[] so that is a problem as i need Wrapper class as an argument for(T
     * val:varargs) System.err.printf("%s ",val); System.err.println(); }
     */
  }
  