#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, len, vf, va, k;
  cin >> n >> len >> vf >> va >> k;
  long long bl = (n + k - 1) / k;
  double eff = static_cast<double>(va - vf) / (va + vf);
  double koef = (va + (bl + (bl - 1) * eff - 1) * vf);
  double ta = len / koef;
  double ans = ta * (bl + (bl - 1) * eff);
  cout << setprecision(15) << ans << endl;
  return 0;
}
