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.util.*;
  import java.io.*;
  public class codeforces{
      //SOLUTION BEGIN
  	
  	 void pre() throws Exception{}
  	 long mod =  1000000000;
  	 void solve(int TC) throws Exception{
  		int n=ni();
  		int a[]=new int[n];
  		
  		int max=ni();
  		int maxi=0;
  		for(int i=1;i<n;i++) {
  			
  			a[i]=ni();
  			max&=a[i];
  		}
  		System.out.println(max);
  	 }
  	 
  
      //SOLUTION END
      void hold(boolean b)throws Exception{if(!b)throw new Exception("Hold right there, Sparky!");}
      static boolean multipleTC = true;
      FastReader in;PrintWriter out;
      void run() throws Exception{
          in = new FastReader();
          out = new PrintWriter(System.out);
          
          int T = (multipleTC)?ni():1;
          pre();for(int t = 1; t<= T; t++)solve(t);
          out.flush();
          out.close();
      }
      
      public static void main(String[] args) throws Exception{
          new codeforces().run();
      }
      int bit(long n){return (n==0)?0:(1+bit(n&(n-1)));}
      void p(Object o){out.print(o);}
      void pn(Object o){out.println(o);}
      void pni(Object o){out.println(o);out.flush();}
      String n()throws Exception{return in.next();}
      String nln()throws Exception{return in.nextLine();}
      int ni()throws Exception{return Integer.parseInt(in.next());}
      long nl()throws Exception{return Long.parseLong(in.next());}
      double nd()throws Exception{return Double.parseDouble(in.next());}
  
      class FastReader{
          BufferedReader br;
          StringTokenizer st;
          public FastReader(){
              br = new BufferedReader(new InputStreamReader(System.in));
          }
  
          public FastReader(String s) throws Exception{
              br = new BufferedReader(new FileReader(s));
          }
  
          String next() throws Exception{
              while (st == null || !st.hasMoreElements()){
                  try{
                      st = new StringTokenizer(br.readLine());
                  }catch (IOException  e){
                      throw new Exception(e.toString());
                  }
              }
              return st.nextToken();
          }
  
          String nextLine() throws Exception{
              String str = "";
              try{   
                  str = br.readLine();
              }catch (IOException e){
                  throw new Exception(e.toString());
              }  
              return str;
          }
      }
      class pair{
      	int x, y;
      	pair(int x,int y){
      		this.x=x;
      		this.y=y;
      	}
      }
  }
  