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: Wrong Answer)

import java.util.*;
class Main
{
    static int MOD = 1000000007;
    public static void main (String[] args)
    {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int p = 0;
        int m = n;
        int k = 0;
        while(m > 0){
            m /= 10;
            p++;
            if(m < 10 && m > 0) k = m;
        }
        int ans = 0;
        for(int i = 3; i < p; i++){
            ans += Math.pow(3, i-1) - 3 * ((int) Math.pow(2, i-1) - 2)+ 3;
        }
        if(k - 1 >= 3){
            ans += Math.pow(2, p-1) - 2;
        }
        if(k - 1 >= 5){
            ans += Math.pow(2, p-1) - 2;
        }
        if(k - 1 >= 7){
            ans += Math.pow(2, p-1) - 2;
        }
        for(int i = k *(int) Math.pow(10, p-1) + 3; i <= n; i++){
            if(judge(i)) ans++;
        }
        System.out.println(ans);
    }
    public  static boolean judge(int i){
        boolean b1 = false, b2 = false, b3 = false;
        while(i > 0){
            int k = i % 10;
            if(k != 3 && k != 5 && k != 7) return false;
            if(k == 3) b1 = true;
            else if(k == 5) b2 = true;
            else if(k == 7) b3 = true;
            i /= 10;
        }
        if(b1 && b2 && b3) return true;
        else return false;
    }
}