import java.util.*;
import java.lang.*;
import java.io.*;
 
 
class Depo
{
	public static void main (String[] args) throws java.lang.Exception
	{
		double a1, a2, v01, v02, s, t, a, b, D;
		Scanner in = new Scanner(System.in);
		a1= in.nextDouble(); 
		a2= in.nextDouble(); 
		v01= in.nextDouble();
		v02= in.nextDouble(); 
		s= in.nextDouble(); 
		a= (a1 + a2)/2;
		b= v01 + v02;
		if(a == 0)
			t= s / b;
        else{
			D= b*b + 4*a*s;
			t=(-b + Math.sqrt(D))/(2*a);
		}
		System.out.println(t);
	}
}

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3.2 2.1 3 7.5 20.8 1.45