import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        double a = sc.nextInt();
        double b = sc.nextInt();
        double c = sc.nextInt();
        double d = sc.nextInt();
        double e = sc.nextInt();
        double f = sc.nextInt();
        f += c * c / 4 / a / a + d * d / 4 / b / b - e;
        System.out.println(Math.sqrt(f));
    }
}