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.Collections;
import java.util.List;
import java.util.Scanner;

public class Main {

	public static void main(String args[]) {

		Scanner sc = new Scanner(System.in);
		long N = sc.nextLong();
		int digit = ((int) Math.log10(N)) + 1;
		List<Long> s = sevenfivethree(digit);
		if(s.isEmpty()) {
			System.out.println(0);
			return;
		}

		int ans = 0;
		for(int i=0;i<s.size();i++) {
//			System.out.println(s.get(i) + ":" + ans);
			if(s.get(i) > N) {
				System.out.println(ans);
				return;
			}else {
				ans++;
			}
		}
		System.out.println(ans);
	}

	public static List<Long> sevenfivethree(int N) {
		List<String> s = new ArrayList<>();

		for(int i=N;i>=3;i--) {
			s.addAll(semisevenfivethree(i, ""));
		}

		List<Long> t = new ArrayList<>();

		for(int i=0;i<s.size();i++) {
			String temp = s.get(i);
			if(temp.contains("3") && temp.contains("5") && temp.contains("7")) {
				t.add(Long.parseLong(temp));
//				System.out.println(temp);
			}
		}
		Collections.sort(t);
		return t;
	}

	public static List<String> semisevenfivethree(int N,String a) {

		List<String> s = new ArrayList<>();
		if(N == 0) {
			s.add(a);
			return s;
		}

		List<String> temp = new ArrayList<>();
		temp.addAll(semisevenfivethree(N-1,a+"3"));
		temp.addAll(semisevenfivethree(N-1,a+"5"));
		temp.addAll(semisevenfivethree(N-1,a+"7"));

		s.addAll(temp);
		return s;
	}
}