fn main() {
    let mut abxy = String::new();
    std::io::stdin().read_line(&mut abxy).ok();
    let abxy: Vec<f64> = abxy.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
    let a = abxy[0];
    let b = abxy[1];
    let x = abxy[2];
    let y = abxy[3];

    println!("{}", if (a+b)*x/a > (a+b)*y/b { (a+b)*y/b } else { (a+b)*x/a });
}