#include <bits/stdc++.h>
int main() {
  int a, b, c, d, e;
  int n;
  scanf("%d%d%d%d%d", &a, &b, &c, &d, &e);
  n = (a - 1) / e + 1;
  double r = (double)(n - 1) / (c + d) * (2 * d);
  double B = (double)b / (c * r + d);
  double A = r * B;
  printf("%.12lf", A + B);
}
