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::collections::VecDeque;

#[allow(unused_macros)]
macro_rules! get {
    ([$t:ty] ; $n:expr) => {
        (0..$n)
        .map(|_| get!([$t])).collect::<Vec<_>>()
    };
    ($($t:ty),+ ; $n:expr) => {
        (0..$n).map(|_| get!($($t),+)).collect::<Vec<_>>()
    };
    ([$t:ty]) => {
        rl().split_whitespace()
        .map(|x| x.parse().unwrap())
        .collect::<Vec<$t>>()
    };
    ($t:ty) => {
        rl().parse::<$t>().unwrap()
    };
    ($($t:ty),*) => {
        {
            let line =rl();
            let mut iter = line.split_whitespace();
            ($(iter.next().unwrap().parse::<$t>().unwrap()),*)
        }
    };
}
fn rl() -> String {
    let mut line = String::new();
    std::io::stdin().read_line(&mut line).unwrap();
    line.trim().to_string()
}

fn check(n: usize) -> bool {
    let mut tn = n;
    let mut v = Vec::new();
    while 0 < tn {
        v.push(tn % 10);
        tn /= 10;
    }
    let mut flag3 = false;
    let mut flag5 = false;
    let mut flag7 = false;
    for i in v.iter() {
        if *i == 3 {
            flag3 = true;
        } else if *i == 5 {
            flag5 = true;
        } else if *i == 7 {
            flag7 = true;
        }
    }
    if flag3 && flag5 && flag7 {
        return true;
    }
    false
}

fn main() {
    let n = get!(usize);
    let mut ans = 0;
    let nums = vec![3, 5, 7];
    let mut q = VecDeque::new();
    q.push_back(3);
    q.push_back(5);
    q.push_back(7);
    'outer: while !q.is_empty() {
        let x = *q.front().unwrap();
        q.pop_front().unwrap();
        for i in 0..3 {
            let tx = x * 10 + nums[i];
            if n < tx {
                break 'outer;
            }
            if check(tx) {
                ans += 1;
            }
            q.push_back(tx);
        }
    }
    println!("{}", ans);
}