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];
    let b = ab[1];

    let result: usize = 50 * a + ((50.0 * a as f64) / (0.8 + 0.2 * b as f64)).floor() as usize;
    println!("{}", result);
}