#include <bits/stdc++.h>
using namespace std;
using ll = long long;
template<class T,class U> using P = pair<T,U>;
template<class T> using vec = vector<T>;
template<class T> using vvec = vector<vec<T>>;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    double A,B,P,Q,R;
    cin >> A >> B >> P >> Q >> R;
    cout << fixed << setprecision(10) << B+(P*B-Q*(B-A))/(R+Q) << endl;
}
