#include <bits/stdc++.h>
using namespace std;
int main() {
  int l, d, v, g, r;
  cin >> l >> d >> v >> g >> r;
  if (d % ((g + r) * v) >= g * v) l += (g + r) * v - d % ((g + r) * v);
  cout << fixed << l * 1.0 / v;
  return 0;
}
