#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main(){
  int d;cin>>d;
  vector<int> a(d+1);
  for(int i = 0; d >= i; i++){
    cin>>a[i];
  }
  reverse(a.begin(),a.end());
  for(int i = 0; d-2 > i; i++){
    a[i+2]+=a[i];
    a[i] = 0;
  }
  int st = d;
  for(int i = 0; d >= i; i++){
    if(a[i]){
      st = min(st,i);
    }
  }
  cout << d-st << endl;
  for(int i = d; st <= i; i--){
    cout << a[i];
    if(i != st)cout << " ";
  }
  cout << endl;
}