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 t = NN;
        var ans = new int[t];
        for (var u = 0; u < t; ++u)
        {
            var s = ReadLine();
            var list = new int[s.Length];
            ans[u] = int.MaxValue;
            Permutate(s.Length, perm =>
            {
                var d = 0;
                for (var i = 0; i < perm.Length; ++i) d = d * 10 + s[perm[i]] - '0';
                var sq = (int)Math.Sqrt(d);
                if (sq * sq == d) ans[u] = Math.Min(ans[u], d);
            });
            if (ans[u] == int.MaxValue) ans[u] = -1;
        }
        WriteLine(string.Join("\n", ans));
    }
    static void Permutate(int n, Action<int[]> action)
    {
        var seed = new int[n];
        for (var i = 0; i < n; ++i) seed[i] = i;
        var used = new bool[n];
        var perm = new int[n];
        Permutate(0, seed, perm, used, action);
    }
    static void Permutate(int pos, int[] seed, int[] perm, bool[] used, Action<int[]> action)
    {
        if (pos == used.Length) action(perm);
        for (var i = 0; i < used.Length; ++i)
        {
            if (used[i]) continue;
            perm[pos] = seed[i];
            used[i] = true;
            Permutate(pos + 1, seed, perm, used, action);
            used[i] = false;
        }
    }
}