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

public class Hello
{
    static void Main()
    {
        var n = int.Parse(Console.ReadLine().Trim());
        Console.WriteLine(getAns(n));
    }
    static int getAns(int n)
    {
        if (n <= 99) return n / 3 - 3;
        var d = n.ToString().Length;
        var ans = (int)Pow(4, d - 1) + 14;
        var k = "0369";
        var k2 = new int[] { 3, 6, 9 };
        var q = new Queue<string>();
        var p1 = n.ToString()[0] - '0';
        foreach (var x in k2)
            if (x <= p1) q.Enqueue(x.ToString());
        while (q.Count() > 0)
        {
            var w = q.Dequeue();
            if (w.Length == d)
            {
                if (int.Parse(w) <= n) ans++;
            }
            else foreach (var x in k) q.Enqueue(w + x);
        }
        return ans;
    }
}