using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray();
    static int[] NMi => ReadLine().Split().Select(c => int.Parse(c) - 1).ToArray();
    static int[][] NMap(int n) => Enumerable.Repeat(0, n).Select(_ => NMi).ToArray();
    static string[] SList(long n) => Enumerable.Repeat(0, (int)n).Select(_ => ReadLine()).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var t = NN;
        var ans = new long[t];
        for (var u = 0; u < t; ++u)
        {
            var n = long.Parse(ReadLine());
            ans[u] = Fsx(n);
        }
        WriteLine(string.Join("\n", ans));
    }
    static long Fsx(long n)
    {
        var nl = Ints(n);
        var minl = nl.ToList();
        var maxl = nl.ToList();
        for (var i = 0; i < nl.Count / 2; ++i)
        {
            minl[i] = 0;
            maxl[i] = 1;
        }
        var min = Rev(minl);
        var max = Rev(maxl);
        var minq = Sqrt(min);
        var maxq = Sqrt(max) + 1;
        for (var i = minq; i <= maxq; ++i)
        {
            var k = n ^ i;
            if (Sqrt(k) == i) return k;
        }
        return -1;
    }
    static List<int> Ints(long n)
    {
        var tmp = n;
        var ans = new List<int>();
        while (tmp > 0)
        {
            ans.Add((int)(tmp % 2));
            tmp >>= 1;
        }
        return ans;
    }
    static long Rev(List<int> a)
    {
        var ans = 0L;
        for (var i = a.Count - 1; i >= 0; --i) ans = ans * 2 + a[i];
        return ans;
    }
    static long Sqrt(long a)
    {
        var sq = (long)Math.Sqrt(a);
        if (sq * sq > a) --sq;
        return sq;
    }
}