#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b, c, d, e, f;
  cin >> a;
  cin >> b;
  cin >> c;
  cin >> d;
  cin >> e;
  cin >> f;
  int maxi = 0;
  for (int i = 0; i <= min(a, d); i++) {
    maxi = max(maxi, i * e + f * (min(b, min(c, d - i))));
  }
  cout << maxi << endl;
  return 0;
}
