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 Rust (1.15.1) (judge verdict: Accepted)

use std::io::*;

fn check(mut x: u64) -> bool {
    let mut san = false;
    let mut go = false;
    let mut siti = false;
    while x > 0 {
        match x % 10 {
            7 => siti = true,
            5 => go = true,
            3 => san = true,
            _ => continue,
        }
        x /= 10;
    }
    san && go && siti
}

fn main() {
    let mut s: String = String::new();
    std::io::stdin().read_to_string(&mut s).ok();
    let mut itr = s.trim().split_whitespace();

    let n: u64 = itr.next().unwrap().parse().unwrap();

    let mut ans = 0;
    let mut q = std::collections::VecDeque::new();
    q.push_back(3);
    q.push_back(5);
    q.push_back(7);
    while let Some(x) = q.pop_front() {
        if x > n {
            break;
        }
        if check(x) {
            ans += 1;
        }
        q.push_back(x * 10 + 3);
        q.push_back(x * 10 + 5);
        q.push_back(x * 10 + 7);
    }
    println!("{}", ans);
}