#include <bits/stdc++.h>
using namespace std;
const double pi = 3.14159265358979323846;
const double E = 2.7182818284590452354;
const struct __ {
  ios_base::Init i;
  int s;
  __() : s(ios_base::xalloc()) {
    srand(time(NULL));
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
  }
} _;
inline ostream& operator<<(ostream& o, const __&) {
  o.iword(_.s) = 0;
  return o << '\n';
}
template <class T>
inline ostream& operator,(ostream& o, const T& x) {
  if (o.iword(_.s))
    o << ' ';
  else
    o.iword(_.s) = 1;
  return o << x;
}
template <>
inline ostream& operator, <__>(ostream& o, const __&) {
  return o << _;
}
template <class I>
inline void in(I A, I B) {
  while (A != B) {
    cin >> *A;
    ++A;
  }
}
template <class I>
inline void out(I A, I B, char D = ' ') {
  if (A != B) {
    cout << *A;
    while (++A != B) {
      cout << D << *A;
    }
  }
  cout << _;
}
template <class T>
inline T sq(const T& X) {
  return X * X;
}
template <class T>
inline T power(T X, int Y) {
  assert(Y >= 0 && !(X == 0 && Y == 0));
  T R = (Y & 1) ? X : 1;
  while (Y >>= 1) {
    X *= X;
    if (Y & 1) R *= X;
  }
  return R;
}
int main() {
  long long a1, a2, a3, a4, a5, a6;
  cin >> a1 >> a2 >> a3 >> a4 >> a5 >> a6;
  cout << sq(a6 + a1 + a2) - (sq(a2) + sq(a4) + sq(a6)) << _;
}
