#include <bits/stdc++.h>
using namespace std;
void Fast_Read_Out() {
  ios_base::sync_with_stdio(0);
  cin.tie(), cout.tie();
}
void Random() {
  unsigned int seed;
  asm("rdtsc" : "=A"(seed));
  srand(seed);
}
unsigned int Time() {
  unsigned int time = clock() / 1000.00;
  return time;
}
const int inf = int(1e9) + 123;
int main() {
  Random();
  Fast_Read_Out();
  long double l, d, v, g, r;
  cin >> l >> d >> v >> g >> r;
  long double t = l / v;
  long double a = d / v;
  while (a >= g + r) a -= g + r;
  if (a >= g) t += g + r - a;
  cout << fixed << t;
}
