#include <bits/stdc++.h>
using namespace std;
#define int long long

int T;

signed main(){
  cin>>T;
  assert(1 <= T && T <= 2e5);
  int M = 1ll<<30;
  for(int i = 0; i < T; i++){
  	int N; cin>>N;
  	assert((1 <= N) && (N < M));
  	int mi = -1;
  	int mi2 = -1;
  	for(int j = 0; j < 60; j++){
  		if(N & (1ll<<j)){
  			if(mi == -1) mi = j;
  			else if(mi2 == -1) mi2 = j;
  		}
  	}
  	if(mi2 == -1){
  		cout << -1 << "\n";
  		continue;
  	}
  	else{
  		cout << (1ll<<mi2) - (1ll<<mi) << "\n";
  		continue;
  	}
  }
}