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.*;

public class Main
{
  public static Scanner sc = new Scanner(System.in);

  public static long n;

  public static int dfs(String s) {
    if (Long.parseLong(s) > n) {
      return 0;
    }

    int ans = 0;
    if (s.contains("7") && s.contains("5") && s.contains("3")) {
      ans = 1;
    }

    ans += dfs(s + "7");
    ans += dfs(s + "5");
    ans += dfs(s + "3");

    return ans;
  }

  public static void main(String args[])
  {
    n = Long.parseLong(sc.next());

    System.out.println(dfs("0"));
  }
}