codevita bike

import java.lang.*;
import java.util.*;
import java.math.*;
class bike
{
    public static void main(String args[])
    {
        double x,y,d,dd,vx,vy,z,dnew=0;
        Scanner t = new Scanner(System.in);
        x = t.nextDouble();
        y = t.nextDouble();
        vx = t.nextDouble();
        vy = t.nextDouble();
        if(x<=0||y<=0||vx<=0||vy<=0)
            System.out.println("Invalid input");
        else
        {
            d= x+y;
            while(true)
            {
                x = x-vx;
                y = y-vy;
                z = (x*x)+(y*y);
                dnew = Math.sqrt(z);
                if(dnew>d)
                {
                    dd = new BigDecimal(d).setScale(11, BigDecimal.ROUND_HALF_UP).doubleValue();
                    System.out.println(dd);

                    break;
                }
                d=dnew;
            }
        }
    }
}