#include <bits/stdc++.h>
using namespace std;
long long int power(long long int a, long long int n) {
  long long int res = 1;
  while (n > 0) {
    if (n & 1)
      res = ((res % 1000000007) * (a % 1000000007)) % 1000000007, n--;
    else
      a = ((a % 1000000007) * (a % 1000000007)) % 1000000007, n /= 2;
  }
  return res;
}
long long int nCr(long long int n, long long int r) {
  if (r > n) return 0;
  double res = 1;
  for (long long int i = 1; i <= r; i++) res = (res * (n - r + i)) / i;
  return (long long int)(res + 0.01);
}
void solve() {
  long long int l, d, v, g, r;
  cin >> l >> d >> v >> g >> r;
  long long int t = d / v;
  std::cout << std::fixed;
  std::cout << std::setprecision(7);
  if (t == 0) {
    cout << (l * 1.0) / v;
    return;
  } else {
    long long int x = t % (g + r);
    if (x < g) {
      cout << (l * 1.0) / v;
      return;
    }
    if (x >= g) {
      double ans = t;
      ans += (r + g - x);
      ans += ((l - d) * 1.0) / v;
      cout << ans << endl;
      return;
    }
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long int t = 1;
  while (t--) {
    solve();
  }
}
