#include <cstdio>
#include <vector>
#include <iostream>
#include <deque>
#include <queue>
#include <tuple>
#include <boost/rational.hpp>
#include <boost/multiprecision/cpp_int.hpp>
#include <boost/multiprecision/cpp_dec_float.hpp>
#include <bitset>
#include <bit>

typedef long long i64;
typedef unsigned long long ui64;

using namespace std;
using namespace boost;
namespace mp = boost::multiprecision;

template<typename T>
inline void output(const T elem) {
    std::cout << elem << std::endl;
}

template<typename T>
inline void output(const vector<T>& vec) {
    for (T elem : vec) {
        std::cout << elem << " ";
    }
    std::cout << std::endl;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << setprecision(15);
    i64 T;
    cin >> T;
    for (i64 i = 1; i < T+1; i++)
    {
        ui64 N;
        cin >> N;
        if (popcount(N) <= 1) {
            output(-1);
        }
        else {
            ui64 answer = 0;
            bool necessary = false;
            for (i64 i = 0; i < 32; i++)
            {
                if (necessary) {
                    if ((N >> i) & 1) {
                        necessary = false;
                        break;
                    }
                }
                else {
                    if ((N >> i) & 1) {
                        necessary = true;
                    }
                }

                if (necessary) {
                    answer |= (1UL << i);
                }
            }
            output(answer);
        }
    }
    return 0;
}