fn main() {
    let mut ans = 0;
    for m in 1..=12 {
        let eom = match m {
            2 => 28,
            4 | 6 | 9 | 11 => 30,
            _ => 31,
        };
        for d in 1..=eom {
            if m == ((d / 10) + (d % 10)) {
                ans += 1;
            }
        }
    }

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