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 Main {
          ///////----------------input----------------//////
  ///////----------------input----------------//////
  
          static BufferedReader br= new BufferedReader(new
                  InputStreamReader(System.in));
          static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
          static StringTokenizer st;
          static byte[] buffer =new byte[10*1024];
          static int index;
          static InputStream input_stream= System.in;
          static int total;
  
          static String ns() throws IOException
          {
              StringBuilder sb = new StringBuilder();
              int n = read();
              while (isWhiteSpace(n))
                  n = read();
              while (!isWhiteSpace(n)) {
                  sb.append((char)n);
                  n = read();
              }
              return sb.toString();
          }
  
          static int read() throws IOException
          {
              if(total<0)
                  throw new InputMismatchException();
              if(index>=total) {
                  index=0;
                  total= input_stream.read(buffer);
                  if(total<=0)
                      return -1;
              }
              return buffer[index++];
          }
          static int ni() throws IOException
          {
              int integer=0;
              int n= read();
              while(isWhiteSpace(n))
                  n= read();
              int neg=1;
              if(n=='-') {
                  neg=-1;
                  n= read();
              }
              while(!isWhiteSpace(n)) {
                  if(n>='0'&&n<='9') {
                      integer*=10;
                      integer+=n-'0';
                      n= read();
                  }
                  else throw new InputMismatchException();
              }
              return neg*integer;
          }
  
          static long nl() throws IOException
          {
              long number=0;
              int n= read();
              while(isWhiteSpace(n))
                  n= read();
              long neg=1l;
              if(n=='-') {
                  neg=-1l;
                  n= read();
              }
              while(!isWhiteSpace(n)) {
                  if(n>='0'&&n<='9') {
                      number*=10l;
                      number+=(long)(n-'0');
                      n= read();
                  }
                  else throw new InputMismatchException();
              }
              return neg*number;
          }
  
          static double nd() throws IOException
          {
              double doub=0;
              int n= read();
              while(isWhiteSpace(n))
                  n= read();
              int neg=1;
              if(n=='-') {
                  neg=-1;
                  n= read();
              }
              while(!isWhiteSpace(n)&&n!='.') {
                  if(n>='0'&&n<='9') {
                      doub*=10;
                      doub+=n-'0';
                      n= read();
                  }
                  else throw new InputMismatchException();
              }
  
              if(n=='.') {
                  n= read();
                  double temp=1;
                  while(!isWhiteSpace(n)) {
                      if(n>='0'&&n<='9') {
                          temp/=10;
                          doub+=(n-'0')*temp;
                          n= read();
                      }
                      else throw new InputMismatchException();
                  }
              }
              return doub*neg;
          }
  
          static String nsl() throws IOException
          {
              String str = "";
              try
              {
                  str = br.readLine();
              }
              catch (IOException e)
              {
                  e.printStackTrace();
              }
              return str;
          }
          static boolean isWhiteSpace(int n) {
              if(n==' '|| n=='\n'|| n=='\r'|| n=='\t'|| n==-1)
                  return true;
              return false;
          }
  
          ///////-------------output-----------------//////
          static public void p(String str) throws IOException {
              bw.append(str);
          }
          static public void pn(String str) throws IOException {
              p(str);
              bw.append("\n");
          }
          static public void close()throws IOException {
              bw.close();
          }
          static public void flush()throws IOException {
              bw.flush();
          }
          public static int MOD=1000000007;
          public static long powerOfNumbers(long a,long b) {
              long ans=1;
              while(b>0)
              {
                  if(b%2==1)
                      ans=(ans*a)%MOD;
  
                  a=(a*a)%MOD;
                  b>>=1;
              }
  
  
              return ans;
  
          }
  
          public static void main(String args[]) throws IOException {
  
              int t=ni();
              while(t-->0) {
                  int n=ni();
                  int[] arr=new int[n];
                  int min=Integer.MAX_VALUE;
                  for(int i=0;i<n;i++){
                      arr[i]=ni();
                      min=Math.min(min,arr[i]);
                  }
                  int and=arr[0];
                  for(int i=1;i<n;i++){
                      and=and&arr[i];
                  }
                  pn(and+"");
  
  
              }
  
  
              flush();
          }
  
  
  
  
  
  
  
  
      }
  
  