#include <bits/stdc++.h>
using namespace std;

#define int long long
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define repi(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define all(x) (x).begin(),(x).end()
#define pb push_back
#define mp make_pair
#define mt make_tuple

typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;

const int inf = 1LL<<60;
const int mod = 1e9 + 7;
const double eps = 1e-9;

/*{
}*/

signed main()
{
  int d;
  cin >> d;

  vi a(d+1);
  rep(i, d+1) cin >> a[i];

  reverse(all(a));

  rep(i, d-2){
    a[i+2] += a[i];
    a[i] -= a[i];
  }

  vi ans;
  bool f = false;
  rep(i, d){
    if(f){
      ans.pb(a[i]);
    }else{
      if(a[i] != 0){
        f = true;
        ans.pb(a[i]);
      }
    }
  }

  reverse(all(ans));

  cout << ans.size() << endl;
  cout << a[d];
  rep(i, ans.size()){
    cout << " " << ans[i];
  }
  cout << endl;

  return 0;
}