#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    if (popcount(ull(n)) == 1) {
      cout << -1 << '\n';
    }
    else {
      int x = 0;
      for (int i = 0; i < 30; ++i) {
        if (n & (1 << i)) {
          if (x == 0) {
            x = -(1 << i);
          }
          else {
            x += (1 << i);
            break;
          }
        }
      }
      cout << x << '\n';
    }
  }
  return 0;
}