fn main() {
    let mut ab = String::new();
    std::io::stdin().read_line(&mut ab).ok();
    let ab: Vec<usize> = ab.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
    let a = ab[0] % 12;
    let b = ab[1] % 60;

    let orgb = b;
    let a = b as f64 / 2. + a as f64 * 30.;
    let b = b as f64 * 6.;
    if a == b {
        println!("0");
        return;
    }
    let start = if b > a {
        (60 - orgb) * 60
    } else {
        0
    };
    let b = if start > 0 {
        b - 360.
    } else {
        b
    };
    for i in start..7200 {
        let i = i as f64;
        let ni = i + 1.;
        let prev_a = a + i / 120.;
        let prev_b = b + i * 6. / 60.;
        let next_a = a + ni * 30. / 3600.;
        let next_b = b + ni * 6. / 60.;
        if next_a == next_b {
            println!("{}", ni as usize);
            return;
        }
        if prev_b < prev_a && next_a < next_b {
            println!("{}", i as usize);
            return;
        }
    }
}