using System;
using System.Linq;
using System.Collections.Generic;
using System.IO;

class MyClass
{
    public static void Solve()
    {
        var Q = int.Parse(Console.ReadLine());
        for (int _i = 0; _i < Q; _i++)
        {
            var input = Console.ReadLine().Split().Select(int.Parse).ToArray();
            var A = input[0];
            var B = input[1];
            var C = input[2];
            var queue = new Queue<int[]>();
            queue.Enqueue(new[] { A, 0 });
            var ans = 0;
            while (A > 0)
            {
                if (A % C == 0)
                {
                    A /= C;
                    ans++;
                }
                else
                {
                    A -= A % C;
                    ans++;
                }
            }
            if (A != 0)
            {
                Console.WriteLine(-1);
            }
            else
            {
                Console.WriteLine((long)B * ans);
            }
        }
    }

    public static void Main()
    {
        var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
        Console.SetOut(sw);
        Solve();
        Console.Out.Flush();
    }
}