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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.ArrayList;
import java.util.Iterator;
import java.util.Scanner;

public class Main {
    static long n;

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        n = sc.nextLong();
        sc.close();

        ArrayList<Long> list = new ArrayList<>();

        dfs(list, 0);

        Iterator<Long> itr = list.iterator();

        while (itr.hasNext()) {
            String s = itr.next().toString();
            if (!(s.contains("3") && s.contains("5") && s.contains("7"))) {
                itr.remove();
            }
        }

        System.out.print(list.size());
    }

    public static void dfs(ArrayList<Long> list, long x) {
        if (x <= n) {
            list.add(x);
        } else {
            return;
        }

        dfs(list, x * 10 + 3);
        dfs(list, x * 10 + 5);
        dfs(list, x * 10 + 7);
    }
}