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)

// 標準入力から一行を読み取り、指定の型に変換する
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()
}

// 753数の数を再帰的に求める.
fn chk_753(n: u64, value: u64, bit753: u8, count: &mut u64) {
    if value > n { return; }
    if bit753 & 7 == 7 { *count += 1; }

    // add 7
    chk_753(n, value * 10 + 7, bit753 | 4, count);
    // add 5
    chk_753(n, value * 10 + 5, bit753 | 2, count);
    // add 3
    chk_753(n, value * 10 + 3, bit753 | 1, count);
}

fn main() {
    let n: u64 = read();
    let mut count: u64 = 0;
    chk_753(n, 0, 0, &mut count);

    println!("{}", count);
}