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#include<bits/stdc++.h>
#define inf 0x3f3f3f3f
#define maxm 100005
#define maxn 2005
#define PII pair<int, int>
#define fi first
#define se second
typedef long long ll;
typedef unsigned long long ull;
using namespace std;
const double pi = acos(-1);
const int mod = 998244353;
const double eps = 1e-10;
const int N =1e2+10;
int n;
int a[N];
int main() {
    ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
    //int a,b,c;
    int t;
    cin>>t;
    while(t--){
    cin>>n;
    for(int i=1;i<=n;i++)cin>>a[i];
    int res=a[1];
    for(int i=2;i<=n;i++)res&=a[i];
    cout<<res<<endl;
    }
    return 0;
}