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 (1.42.0) (judge verdict: Accepted)

#![allow(
    non_snake_case,
    unused_variables,
    unused_assignments,
    unused_mut,
    unused_imports,
    dead_code
)]
//use permutohedron::LexicalPermutation as _;
use proconio::{fastout, input, marker::*};
use std::collections::*;
//use std::cmp::*;
//use std::num;
//use petgraph::unionfind::UnionFind;

#[fastout()]
fn main() {
    input! {
        N:i64
    }
    if N < 357 {
        println!("0");
        return;
    }

    let l = N.to_string();

    let ans = dfs(0, N);
    println!("{}", ans);
}
fn dfs(x: i64, N: i64) -> i64 {
    let mut t = 0;
    if x > N {
        return 0;
    } else if is753(x) {
        t += 1;
    }
    t += dfs(x * 10 + 3, N);
    t += dfs(x * 10 + 5, N);
    t += dfs(x * 10 + 7, N);
    t
}
fn is753(x: i64) -> bool {
    let s = x.to_string();
    if s.find('3') == None || s.find('5') == None || s.find('7') == None {
        false
    } else {
        true
    }
}