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{
  static int N;
  static Set<Long> set;
  public static void main(String[]args){
    Scanner sc =  new Scanner(System.in);
    N = Integer.parseInt(sc.nextLine());
    set = new HashSet<>();
    
    long n = 0;
    func(n);
    System.out.println(set.size());
  }
  public static void func(long n){
    if(n > N){
      return;
    }
    boolean c3 = false;
    boolean c5 = false;
    boolean c7 = false;
    String s = n + "";
    for(int i = 0; i < s.length(); i++){
      if(s.charAt(i) == '3'){
        c3 = true;
      }else if(s.charAt(i) == '5'){
        c5 = true;
      }else if(s.charAt(i) == '7'){
        c7 = true;
      }
    }
    if(c3 && c5 && c7){
      set.add(n);
    }
    
    func(n*10+3);
    func(n*10+5);
    func(n*10+7);
  }
}