#if defined(__GNUG__) && !defined(__clang__)
#include <bits/stdc++.h>
#endif

#define inf(T) (numeric_limits<T>::min())
#define sup(T) (numeric_limits<T>::max())
#define rep(i,n) for (int i = 0; i < (n); i++)
#define asc(c) (c).begin(), (c).end()
#define desc(c) (c).rbegin(), (c).rend()
#define mp(...) make_pair(__VA_ARGS__)
#define mt(...) make_tuple(__VA_ARGS__)

using namespace std;

using ll = long long;
using ld = long double;

template <class Key>          using uset = unordered_set<Key>;
template <class Key, class T> using umap = unordered_map<Key, T>;

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

  int d;
  cin >> d;
  vector<int> as(d + 1);
  rep(i, d + 1) cin >> as[i];
  for (int i = d; i >= 3; i--) {
    as[i - 2] += as[i];
    as[i] = 0;
  }
  int n_digit = 0;
  for (int i = 2; i > 0; i--) {
    if (as[i] == 0) continue;
    n_digit = i;
    break;
  }
  cout << n_digit << endl;
  rep(i, n_digit + 1) {
    cout << as[i];
    if (i != n_digit) cout << ' ';
  }
  cout << endl;

  return 0;
}