// includes
#include <bits/stdc++.h>

// macros
#define ll long long int
#define pb emplace_back
#define mk make_pair
#define pq priority_queue
#define FOR(i, a, b) for(int i=(a);i<(b);++i)
#define rep(i, n) FOR(i, 0, n)
#define rrep(i, n) for(int i=((int)(n)-1);i>=0;i--)
#define all(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end())
#define FI first
#define SE second
using namespace std;

//  types
typedef pair<int, int> P;
typedef pair<ll, int> Pl;
typedef pair<ll, ll> Pll;
typedef pair<double, double> Pd;
 
// constants
const int inf = 1e9;
const ll linf = 1LL << 50;
const double EPS = 1e-10;
const int mod = 1e9 + 7;

// solve
template <class T>bool chmax(T &a, const T &b){if(a < b){a = b; return 1;} return 0;}
template <class T>bool chmin(T &a, const T &b){if(a > b){a = b; return 1;} return 0;}
template <typename T> istream &operator>>(istream &is, vector<T> &vec){for(auto &v: vec)is >> v; return is;}


int main(int argc, char const* argv[])
{
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  int d;
  cin >> d;
  vector<int> a(d + 1);
  cin >> a;
  int f1 = 0, f0 = 0, f_1 = 0;
  for(int i = 0; i <= d; i++){
    f1 += a[i];
    f0 += (i == 0 ? a[i]: 0);
    f_1 += a[i] * (i % 2 == 1 ? -1: 1);
  }
  int c = f0;
  int A = (f1 + f_1) / 2 - c;
  int b = (f1 - f_1) / 2;
  if(A != 0){
    cout << 2 << endl;
    cout << c << " " << b << " " << A << endl;
  }else if(b != 0){
    cout << 1 << endl;
    cout << c << " " << b << endl;
  }else{
    cout << 0 << endl;
    cout << c << endl;
  }
	return 0;
}