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();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var dic = new Dictionary<string, int>();
        for (var i = 1; ; ++i)
        {
            var d = i * i;
            if (d > 1_000_000_000) break;
            var s = d.ToString().ToList();
            s.Sort();
            var p = string.Concat(s);
            if (!dic.ContainsKey(p)) dic[p] = d;
        }
        var t = NN;
        var ans = new int[t];
        for (var u = 0; u < t; ++u)
        {
            var s = ReadLine();
            ans[u] = Perm(dic, s);
        }
        WriteLine(string.Join("\n", ans));
    }
    static int Perm(Dictionary<string, int> dic, string s)
    {
        var l = s.ToList();
        l.Sort();
        var fnz = l.FindIndex(c => c != '0');
        for (var i = fnz; i >= 0; --i)
        {
            var p = string.Concat(l.Skip(i));
            if (dic.ContainsKey(p)) return dic[p];
        }
        return -1;
    }
}