fn main() { let mut ab = String::new(); std::io::stdin().read_line(&mut ab).ok(); let ab: Vec = 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); }