#include<iostream>
#include<vector>
#include<string>
#include<algorithm>	
#include<map>
#include<set>
#include<utility>
#include<cmath>
#include<cstring>
#include<queue>
#include<stack>
#include<cstdio>
#include<sstream>
#include<iomanip>
#include<assert.h>
#define loop(i,a,b) for(int i=a;i<b;i++) 
#define rep(i,a) loop(i,0,a)
#define pb push_back
#define mt make_tuple
#define all(in) in.begin(),in.end()
#define shosu(x) fixed<<setprecision(x)
using namespace std;
//kaewasuretyuui
typedef long long ll;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<pii> vp;
typedef vector<vp> vvp;
typedef vector<string> vs;
typedef vector<double> vd;
typedef tuple<int,int,int> tp;
typedef vector<tp> vt;
typedef vector<vd> vvd;
typedef pair<int,pii> pip;
typedef vector<pip>vip;
const double PI=acos(-1);
const double EPS=1e-7;
const int inf=1e8;
const ll INF=1e16;
int dx[]={0,1,0,-1};
int dy[]={1,0,-1,0};
int main(){
	int n;
	cin>>n;
	vi in(n+1);
	rep(i,n+1)cin>>in[n-i];
	rep(i,max(0,n-2)){
		in[i+2]+=in[i];
		in[i]=0;
	}
	reverse(all(in));
	vi out;
	if(n>=2&&in[2])out.pb(in[2]);
	if(n>=1&&(in[1]||out.size()))out.pb(in[1]);
	out.pb(in[0]);
	cout<<out.size()-1<<endl;
	rep(i,out.size())cout<<out[out.size()-i-1]<<" ";cout<<endl;
}