fn main() {
    let mut ab = String::new();
    std::io::stdin().read_line(&mut ab).ok();
    let ab: Vec<isize> = ab.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
    let a = ab[0] as f64;
    let b = ab[1] as f64;

    let span = 0.00001;
    let mut left = a;
    let mut result = 0.;
    let calc = |x: f64, a: f64, b: f64| { (x - a) * (x - b) };
    while left + span <= b {
        result += calc(left + span/2., a, b) * span;
        left = left + span;
    }
    println!("{:.06}", result);
}