use std::io::*;
use std::str::FromStr;

fn calc(a: i32, b: i32) -> i32 {
    let a = if a >= 12 { a - 12 } else { a };
    if a == 0 && b == 0 {
        return 0;
    }

    let mut x = (a * 60 + b) * 60;
    let mut y = 720 * b;

    let mut ret = 0;
    loop {
        if y < x && y + 12 == x + 1 {
            ret += 1;
            break;
        } else if y < x && y + 12 >= x + 1 {
            break;
        }
        x += 1;
        y += 12;

        ret += 1;
        if x >= 360 * 120 {
            x -= 360 * 120;
        }
        if y >= 360 * 120 {
            y -= 360 * 120;
        }
    }

    ret
}

fn main() {
    let mut s = String::new();
    stdin().read_line(&mut s).ok();
    let mut itr = s.split_whitespace().map(|x| i32::from_str(x).unwrap());
    let (a, b) = (itr.next().unwrap(), itr.next().unwrap());

    println!("{}", calc(a, b));
}