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: Time Limit Exceeded)

use std::io::prelude::*;
use std::io::stdin;
use std::str::FromStr;

fn main() {
    let n: u64 = read();
    if n < 10u64.pow(8) {
        println!("{}", count(n));
    } else {
        if n > 7 * 10u64.pow(8) {
            println!("{}", 8334 + 2 * 5796 + count(n - 7 * 10u64.pow(8)));
        } else if n > 5 * 10u64.pow(8) {
            println!("{}", 8334 + 5796 + count(n - 5 * 10u64.pow(8)));
        } else if n > 3 * 10u64.pow(8) {
            println!("{}", 8334 + count(n - 3 * 10u64.pow(8)));
        } else {
            println!("{}", 8334);
        }
    }
}

fn count(n: u64) -> u64 {
    let mut count = 0;
    'outer: for i in 357..n + 1 {
        let s = i.to_string();
        let mut three = 0;
        let mut five = 0;
        let mut seven = 0;
        for c in s.chars() {
            if c == '3' {
                three += 1;
            } else if c == '5' {
                five += 1;
            } else if c == '7' {
                seven += 1;
            } else {
                continue 'outer;
            }
        }
        if three > 0 && five > 0 && seven > 0 {
            count += 1;
        }
    }
    count
}

fn read<T: FromStr>() -> T {
    let stdin = stdin();
    let token: String = stdin
        .lock()
        .bytes()
        .map(|b| b.unwrap() as char)
        .skip_while(|c| c.is_whitespace())
        .take_while(|c| !c.is_whitespace())
        .collect();
    token.parse().ok().unwrap()
}