#include <bits/stdc++.h>
using namespace std;
double l, d, v, A, B, t1, W, T;
int main() {
  scanf("%lf%lf%lf%lf%lf", &l, &d, &v, &A, &B);
  t1 = d / v;
  W = double(int(t1 / (A + B)));
  t1 -= W * (A + B);
  T += W * (A + B);
  if (t1 < A)
    T += t1;
  else
    T += A + B;
  T += (l - d) / v;
  printf("%.8lf", T);
}
