//Challenge: Accepted
#include <iostream>
#include <algorithm>
#include <utility>
#include <vector>
#define ll long long
#define maxn 100005
#define ff first
#define ss second
#define io ios_base::sync_with_stdio(0);cin.tie(0);
#define pii pair<int, int>
using namespace std;
//#include <bits/extc++.h>
//using namespace __gnu_pbds;
//template<lcass T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
//find by order, order of key
int main() {
io
int t;
cin >> t;
while (t--) {
int k;
cin >> k;
cout << ((k + 3) / 2 - 1) * 2 << "\n";
cout << -1 << "\n";
}
}
