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();
        // Test();
    }
    static void Test()
    {
        var r = new Random();
        var count = 0;
        while (true)
        {
            var n = r.NextInt64(1_000_000_000_000_000_000) + 1;
            var k = r.NextInt64(Math.Min(1000, n)) + 1;
            var m = r.NextInt64(1_000_000_000_000) + 2;
            // 愚直解
            var s1 = All(n, k, m);
            // 作成解
            var s2 = Divide(n, k, m);
            if (s1 != s2)
            {
                WriteLine($"{n} {k} {m}");
                // WriteLine(string.Join("\n", map.Select(m => string.Join(" ", m))));
                WriteLine(s1);
                WriteLine(s2);
                return;
            }
            ++count;
            if (count % 1000 == 0) WriteLine(count);
        }
    }
    static long All(long n, long k, long m)
    {
        var ans = 0L;
        for (var i = n - k + 1; i <= n; ++i)
        {
            var tmp = i;
            while (tmp % m == 0)
            {
                ++ans;
                tmp /= m;
            }
        }
        for (var i = 1L; i <= k; ++i)
        {
            var tmp = i;
            while (tmp % m == 0)
            {
                --ans;
                tmp /= m;
            }
        }
        return ans;
    }
    static void Solve()
    {
        var c = NList;
        var (n, k, m) = (c[0], c[1], c[2]);
        WriteLine(Divide(n, k, m));
    }
    static long Divide(long n, long k, long m)
    {
        return Divs(n, m) - Divs(n - k, m) - Divs(k, m);
    }
    static long Divs(long n, long p)
    {
        if (n < 0) return 0;
        var prev = 1L;
        var ans = 0L;
        while (true)
        {
            var pc = prev * p;
            if (pc / p != prev) break;
            ans += n / pc;
            prev = pc;
        }
        return ans;
    }
}