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# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
class Program
{
	static void Main(string[] args)
	{
		// ���̓t�F�[�Y
        long N = long.Parse(Console.ReadLine());

        long cnt = 0;
        long ret = 0;
        while(true)
        {
            // cnt��1�����₵�Ă���
            cnt++;

            // 4�i���ƍl����cnt=(ex)111 ��555��N�𒴂�����I��
            if (stopCount(cnt, N)) break;

            // cnt��753���ł���Α���
            if (is753Num(cnt, N)) ret += 1;
        }
        //�o��
        Console.WriteLine(ret);
    }
    static bool is753Num(long cnt, long N)
    {
        // cnt(3�i���j��0,1,2�����ȏ㌻��Ă����true
        bool exist0 = false, exist1 = false, exist2 = false, exist4 = false;


        while(cnt > 0)
        {
            switch (cnt % 4)
            {
                case 1:
                    exist0 = true;
                    break;
                case 2:
                    exist1 = true;
                    break;
                case 3:
                    exist2 = true;
                    break;
                case 0:
                    exist4 = true;
                    break;
            }
            cnt /= 4;
        }
        bool e = exist0 && exist1 && exist2;

        //Console.WriteLine(cnt + " " + e);
        return (exist0 && exist1 && exist2 && !exist4);
    }

    static bool stopCount(long cnt, long N)
    {
        string S = "";
        //Console.Write(cnt + " " + N + " " );
        while(cnt > 0)
        {
            switch(cnt%4)
            {
                case 1:
                    S = "3" + S;
                    break;
                case 2:
                    S = "5" + S;
                    break;
                case 3:
                    S = "7" + S;
                    break;
            }
            cnt /= 4;
        }
        //Console.WriteLine(S);
        long convCnt = long.Parse(S);
        if (convCnt > N) return true;
        else return false;
    }

}