Problem:
Score : 300 points

Problem Statement

You are given an integer N. Among the integers between 1 and N (inclusive), how many Shichi-Go-San numbers (literally "Seven-Five-Three numbers") are there?

Here, a Shichi-Go-San number is a positive integer that satisfies the following condition:

When the number is written in base ten, each of the digits 7, 5 and 3 appears at least once, and the other digits never appear.

Constraints

1 \leq N < 10^9

N is an integer.

Input

Input is given from Standard Input in the following format:

N

Output

Print the number of the Shichi-Go-San numbers between 1 and N (inclusive).

Sample Input 1

575

Sample Output 1

4

There are four Shichi-Go-San numbers not greater than 575: 357, 375, 537 and 573.

Sample Input 2

3600

Sample Output 2

13

There are 13 Shichi-Go-San numbers not greater than 3600: the above four numbers, 735, 753, 3357, 3375, 3537, 3557, 3573, 3575 and 3577.

Sample Input 3

999999999

Sample Output 3

26484

Solution in C# (.NET Core 3.1.201) (judge verdict: Accepted)

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Security.Cryptography.X509Certificates;
using static System.Console;

class Program
{
    static void Main(string[] args)
    {
        var N = long.Parse(ReadLine());

        static IEnumerable<long> GetSemi753Num()
        {
            var _357 = new long[] { 3, 5, 7 };
            var q = new Queue<long>(_357);

            while(true)
            {
                var n = q.Dequeue();

                yield return n;

                foreach (var m in _357)
                    q.Enqueue(n * 10 + m);
            }
        }

        static bool Is753Num(long n) => (n.ToString().Select(c => c - '0').Select(x => 1 << x).Aggregate((s, e) => s | e) & 0xA8) == 0xA8;

        var ans = 0;

        foreach(var n in GetSemi753Num().TakeWhile(x => x <= N).Where(x => Is753Num(x)))
            ans++;

        WriteLine(ans);
    }
}