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.Scanner;

public class Main {

    public static void main(String[] args){

        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        System.out.println(call(1, 0, 0, 0, 0, n));

    }

    private static int call(int base, int c3, int c5, int c7, int num, int n) {
        int res = 0;
        if(c3>0 && c5>0 && c7>0 && num <= n) res++;
        if(base == 1000000000) return res;
        res += call(base * 10, c3 + 1, c5, c7, num + 3 * base, n);
        res += call(base * 10, c3, c5+1, c7, num + 5 * base, n);
        res += call(base * 10, c3, c5, c7+1, num + 7 * base, n);
        return res;
    }

}