#include<bits/stdc++.h>

using namespace std;

//directives

#define pb push_back

#define int long long

#define ss second

#define ff first

void solve(){

int n;

cin>>n;

vector<int> arr(n);

for(int i=0; i<n; i++) cin>>arr[i];

vector<int> cnt(32, 0);

for(int i=0; i<32; i++){

for(int j=0; j<n; j++){

// cout<<arr[j]<<" "<<(arr[j] & (1 << i))<<endl;

cnt[i] += (arr[j] & (1 << i)) == 0 ? 0 : 1;

}

}

int ans = 0;

for(int i=0; i<32; i++){

// cout<<i<<" "<<cnt[i]<<endl;

if(cnt[i] > 1){

ans += (1 << i);

}

}

cout<<ans<<endl;

}

int32_t main(){

ios_base::sync_with_stdio(false);

cin.tie(0);

int t=1;

cin>>t;

while(t--) solve();

return 0;

}