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



signed main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << fixed << setprecision(20);
    
    double a,b;
    cin>>a>>b;
    double p,q,r;
    cin>>p>>q>>r;
    double now = p*b-(b-a)*q;
    now = b + (now)/(q+r);
    cout << now << endl;
    
}

