#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b, c, d, e, f;
  cin >> a >> b >> c >> d >> e >> f;
  int s1 = a;
  int s2 = min(b, c);
  long long ans = 0;
  for (int i = 0; i <= d; i++) {
    long long c1 = 1LL * min(i, s1) * e;
    long long c2 = 1LL * min(d - i, s2) * f;
    ans = max(ans, c1 + c2);
  }
  cout << ans;
}
