import java.util.*;

public class Main {
	public static void main (String[] args) {
		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();
		double powans = ((f - e) + (c * c + d * d) / 4) / a;
		System.out.println(Math.sqrt(powans));
	}
}