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)

pub fn read<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}

pub fn read_vec<T: std::str::FromStr>() -> Vec<T> {
    read::<String>()
        .split_whitespace()
        .map(|e| e.parse().ok().unwrap())
        .collect()
}

pub fn read_vec2<T: std::str::FromStr>(n: usize) -> Vec<Vec<T>> {
    (0..n).map(|_| read_vec()).collect()
}

pub fn read_col<T: std::str::FromStr>(n: usize) -> Vec<T> {
    (0..n).map(|_| read()).collect()
}

fn cnt357(n: u64, x: u64) -> u64 {
    let mut ans = 0;
    for i in vec![3, 5, 7] {
        let y = 10 * x + i;
        if y <= n {
            ans += 1 + cnt357(n, y);
        }
    }
    ans
}

fn cnt35(n: u64, x: u64) -> u64 {
    let mut ans = 0;
    for i in vec![3, 5] {
        let y = 10 * x + i;
        if y <= n {
            ans += 1 + cnt35(n, y);
        }
    }
    ans
}

fn cnt37(n: u64, x: u64) -> u64 {
    let mut ans = 0;
    for i in vec![3, 7] {
        let y = 10 * x + i;
        if y <= n {
            ans += 1 + cnt37(n, y);
        }
    }
    ans
}

fn cnt57(n: u64, x: u64) -> u64 {
    let mut ans = 0;
    for i in vec![5, 7] {
        let y = 10 * x + i;
        if y <= n {
            ans += 1 + cnt57(n, y);
        }
    }
    ans
}

fn cnt3(n: u64, x: u64) -> u64 {
    let mut ans = 0;
    let y = 10 * x + 3;
    if y <= n {
        ans += 1 + cnt3(n, y);
    }
    ans
}

fn cnt5(n: u64, x: u64) -> u64 {
    let mut ans = 0;
    let y = 10 * x + 5;
    if y <= n {
        ans += 1 + cnt5(n, y);
    }
    ans
}

fn cnt7(n: u64, x: u64) -> u64 {
    let mut ans = 0;
    let y = 10 * x + 7;
    if y <= n {
        ans += 1 + cnt7(n, y);
    }
    ans
}

fn main() {
    let n: u64 = read();
    let ans = cnt357(n, 0) + cnt3(n, 0) + cnt5(n, 0) + cnt7(n, 0)
        - cnt35(n, 0)
        - cnt37(n, 0)
        - cnt57(n, 0);
    println!("{}", ans);
}