#include <bits/stdc++.h>
using namespace std;
int Mod = 1000000007;
bool check(double d, double t, double v1, double v2, double n) {
  double x1 = (d - t * v1) / (v2 - v1);
  double x2 = (t - x1 * n) / (n - 1);
  if ((x1 - x2) * v2 <= (x1 + x2) * v1)
    return true;
  else
    return false;
}
void bin(double d, double v1, double v2, double n) {
  double low = d / v2;
  double high = d / v1;
  int cnt = 0;
  while (cnt < 100) {
    double mid = (low + high) / 2;
    if (check(d, mid, v1, v2, n) == true)
      high = mid;
    else
      low = mid + 0.000001;
    cnt++;
  }
  cout << setprecision(9) << low << endl;
}
int main() {
  long long a, b, c, l, e, p;
  double n, d, v1, v2, k;
  cin >> a >> b >> c >> l >> e;
  p = a / e;
  if (a % e != 0) p++;
  n = double(p);
  d = double(b);
  v1 = double(c);
  v2 = double(l);
  bin(d, v1, v2, n);
}
