#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using ll = long long;
#define rep(i, s, t) for (ll i = s; i < (ll)(t); i++)
#define all(x) begin(x), end(x)

template <typename T> bool chmin(T& x, T y) {
	return x > y ? (x = y, true) : false;
}
template <typename T> bool chmax(T& x, T y) {
	return x < y ? (x = y, true) : false;
}

struct IOST {
	IOST() {
		ios::sync_with_stdio(false);
		cin.tie(nullptr);
		cout << fixed << setprecision(20);
	}
} IOST;

ll isqrt(ll x) {
	ll tmp = sqrt(x);
	while ((tmp + 1) * (tmp + 1) < x) tmp++;
	while (tmp * tmp > x) tmp--;
	return tmp;
}

void solve() {
	ll n;
	cin >> n;
	ll k = 0;
	for (int i = 60; i >= 0; i--) {
		ll ck = k ^ isqrt(k);
		if (((n >> i) ^ (ck >> i)) & 1) {
			k ^= (1LL << i);
		}
	}
	if ((k ^ isqrt(k)) != n) cout << "-1\n";
	else cout << k << "\n";
}

int main() {
	int t = 1;
	cin >> t;
	rep(i, 0, t) solve();
}