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

class Program
{
    static int NN => int.Parse(ReadLine());
    static long[] NList => ReadLine().Split().Select(long.Parse).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var c = NList;
        var (n, k, m) = (c[0], c[1], c[2]);
        WriteLine(Divs(n, m) - Divs(n - k - 1, m) - Divs(k, m));
    }
    static long Divs(long n, long p)
    {
        var prev = 1L;
        var ans = 0L;
        while (true)
        {
            var pc = prev * p;
            if (pc / p != prev) break;
            ans += n / pc;
            prev = pc;
        }
        return ans;
    }
}