#include <bits/stdc++.h>
#include <atcoder/all>
#include <boost/multiprecision/cpp_dec_float.hpp>
#include <boost/multiprecision/cpp_int.hpp>
namespace mp = boost::multiprecision;
using Bint = mp::cpp_int;
using namespace std;
using namespace atcoder;
#define rep(i, n) for(int i=0;i<(n);++i)
#define rep1(i, n) for(int i=1;i<=(n);i++)
#define ll long long
using mint = modint998244353;
using P = pair<ll,ll>;
using lb = long double;
using T = tuple<ll, ll, ll>;
#ifdef LOCAL
#  include <debug_print.hpp>
#  define dbg(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#  define dbg(...) (static_cast<void>(0))
#endif

int main()
{
    int t;
    cin >> t;
    while(t--) {
        int n;
        cin >> n;
        if(__builtin_popcount(n)==1) {
            cout << -1 << endl;
        }
        else{
            int cnt = 0;
            int sum = 0;
            rep(i,30)  {
                if(n>>i&1) {
                cnt++;
                if(cnt==2) break;
                    
                }
                else sum += (1<<i);
            }
            cout << sum+1 << endl;
        }
    }
    return 0;
}