#include <bits/stdc++.h>
using namespace std;
map<long long, long long> mp, vis;
vector<long double> vv;
vector<pair<long long, long long> > vp;
string s, q;
char c;
int main() {
  long double t = 0, n, m, l, r, mn = 0, mx = 0, ans = 0, nm = 0, cnt = 0, x, y,
              z, d, v, g;
  cin >> l >> d >> v >> g >> r;
  l -= d;
  t += d / v;
  long long p = (long long)t / (long long)(g + r);
  x = t - (p * (g + r));
  if (x >= g) t += r - (x - g);
  t += l / v;
  cout << setprecision(10) << fixed << t;
}
