#include <bits/stdc++.h>

using namespace std;

#define REP(i,n) for(int i=0; i<(int)(n); i++)

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  vector<int> x(3), y(3);

  REP (i, 3) { cin >> x[i]; x[i] *= 2; }
  REP (i, 3) cin >> y[i];

  int sum = accumulate(x.begin(), x.end(), 0);
  REP (i, 3) x[i] = sum - x[i];

  sort(x.begin(), x.end());
  sort(y.rbegin(), y.rend());

  int ret = 0;
  REP (i, 3) ret += x[i] * y[i];
  cout << ret << endl;
  
  return 0;
}