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

int a[100005];

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    double a, b, p, q, r;
    cin >> a >> b >> p >> q >> r;

    double dist = p * b - (b - a) * q;
    cout << fixed << setprecision(9);
    cout << b + (dist / (q + r)) << endl;
}
