#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define rep(i, n) for (int i = 0; i < (n); i++)
#define P pair<int, int>

int main() {
  double a, b, c, d, e, f;
  cin >> a >> b >> c >> d >> e >> f;

  cout << fixed << setprecision(10) << sqrt(f - (e/a) + (c*c+d*d)/(4*a*a)) << endl;

}