#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for(ll i = 0, i##_len = (n); i < i##_len; ++i)
#define rep2(i, x, n) for(ll i = x, i##_len = (n); i < i##_len; ++i)
#define all(n) begin(n), end(n)
using ll = long long;
using P = pair<ll, ll>;
using vi = vector<int>;
using vl = vector<ll>;
using vs = vector<string>;
using vc = vector<char>;
using vb = vector<bool>;
using vd = vector<double>;
vi dir = {-1, 0, 1, 0, -1, -1, 1, 1, -1};

int main() {
  double a, b, c, d, e, f;
  cin >> a >> b >> c >> d >> e >> f;
  double l = c / a, m = d / a, n = (e - f) / a;
  double r = sqrt((l * l + m * m - 4.0 * n) / 4.0);
  printf("%.10f\n", r);
}