#include <bits/stdc++.h>

#define rep(i,n) for(int i = 0; i < (n); ++i)

typedef long long ll;

using namespace std;

const double eps = 1e-9;


int main() {
	long double tf, vf, hf, td, vd, hd, backup_tf;
	cin >> tf >> vf >> hf >> td >> vd >> hd;
	
	//cout << endl << " " << tf << " " << vf << " " << hf << " " << td << " " << vd << " " << hd << endl;

	backup_tf = tf;
	td -= tf;
	tf = 0;

	long double t_fall = sqrt(2*hf);
	long double tj = sqrt(2.0/3.0*hd);
	
	if (vf >= vd){
		//cout << "fast" << endl;
		cout << setprecision(15) << 2*(t_fall*vf)/vd + td + backup_tf << endl;
		return 0;
	}
	
	long double t_samex = (vd*td)/(vd-vf);

	//cout << "t_fall " << t_fall << " tj " << tj << " t_samex " << t_samex << endl;

	if(t_samex > t_fall) {	
		//cout << "s > f"<< endl;
		cout << setprecision(15) << 2*(t_fall*vf)/vd + td + backup_tf << endl;
		return 0;
	}
	if (t_samex >= tj) {
		//cout << "s >= tj" << endl;
		if ((hf - 0.5*t_samex*t_samex) <= hd) {
			//cout << "1rr" << endl;
			cout << setprecision(15) << 2*t_samex - td + backup_tf << endl;
			return 0;
		}
		//cout << "2rr" << endl;
		long double t_hd = sqrt(2*(hf-hd));
		cout << setprecision(15) << t_hd + vf*t_hd/vd + backup_tf << endl;
		return 0;
	}
	//cout << "bs" << endl;
	long double l = 0;
	long double r = tj;
	while(r-l > eps) {
		long double mid = (r+l)/2.0;
		long double yf = hf - 0.5*(mid+td)*(mid+td);
		long double ypes = hd - 1.5*(tj-mid)*(tj-mid);
		if(yf < ypes) 
			r = mid;
		else
			l = mid;
	}
	l = max(l+td, t_samex);
	cout << setprecision(15) << l + l*vf/vd + backup_tf << endl;
					
	return 0;
}