#include <bits/stdc++.h>
using namespace std;

int main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  double a, b;
  cin >> a >> b;
  double p, q, r;
  cin >> p >> q >> r;
  double res = b + (b * p - (b - a) * q) / (q + r);
  cout << fixed << setprecision(15) << res << '\n';
}

