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

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 q = NN;
        var ans = new long[q];
        for (var u = 0; u < q; ++u)
        {
            var c = NList;
            if (c[2] == 1) ans[u] = -1;
            else
            {
                var tmp = c[0];
                var list = new List<int>();
                while (tmp > 0)
                {
                    list.Add(tmp % c[2]);
                    tmp /= c[2];
                }
                if (list.Count == 1) ++ans[u];
                else
                {
                    if (list[^2] < c[2] - 1 && list[^1] == 1) ans[u] += 2;
                    else if (list[^2] == 0) ans[u] += 2;
                    else ans[u] += 3;
                    for (var i = 0; i + 2 < list.Count; ++i)
                    {
                        ++ans[u];
                        if (list[i] > 0) ++ans[u];
                    }
                }
                ans[u] *= c[1];
            }
        }
        WriteLine(string.Join("\n", ans));
    }
}