use proconio::input;

fn main() {
    input! {
        n: i32,
    }

    let mut ans: i32= 0;
    for i in 1..n + 1 {
        let a = i / 100;
        let b = (i - a * 100) / 10;
        let c = i - a * 100 - b * 10;
        if a == 8 || b == 8 || c == 8 {
            ans += 1;
        }
    }

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