int main() {
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    ll n, a, b, c;
    cin >> n >> a >> b >> c;
    ll min1 = LLONG_MAX;
    for(long long i = n / 2 - 1; i <= n;i++) {
        ll res = ((c + b) * i) / (a + b);
        if(min1 > max(max(res * a, (i - res - 1) * b + c * i), (n - i) * a + c * i))
            min1 = max(max(res * a, (i - res - 1) * b + c * i), (n - i) * a + c * i);
    }
    cout << min1;
}