using static System.Math;
using System;

public class Hello
{
    static void Main()
    {
        string[] line = Console.ReadLine().Trim().Split(' ');
        var h = long.Parse(line[0]);
        var a = long.Parse(line[1]);
        getAns(h, a);
    }
    static void getAns(long h, long a)
    {
        var c = 0;
        while (true)
        {
            h /= a;
            c++;
            if (h == 0) break;
        }
        Console.WriteLine((long)Pow(2, c) - 1);
    }
}