#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(ll i=0;i<n;i++)
#define repl(i,l,r) for(ll i=(l);i<(r);i++)
#define per(i,n) for(ll i=n-1;i>=0;i--)
#define lper(i,r,l) for(ll i=r-1;i>=l;i--)
#define fi first
#define se second
#define all(x) (x).begin(),(x).end()
#define CST(x) cout<<fixed<<setprecision(x)
using ll=long long;
using vl=vector<ll>;
using vvl=vector<vector<ll>>;
using pl=pair<ll,ll>;
template<class T> inline bool chmin(T& a, T b){
    if(a>b){a = b;return true;}return false;}
template<class T> inline bool chmax(T& a, T b){
    if(a<b){a=b;return true;}return false;}
const ll MOD=1000000007;
const ll MOD9=998244353;
const int inf=1e9;
const ll INF=4e18;
const ll dy[4]={1,0,-1,0};
const ll dx[4]={0,-1,0,1};
int main(){
    int D;cin>>D;
    vl info(D+1);
    rep(i,D+1)cin>>info[D-i];
    rep(i,D-2){
        info[i+2]+=info[i];
        info[i]=0;
    }
    int a=info[D-2],b=info[D-1],c=info[D];
    if(a==0 and b==0)cout<<0<<endl<<c<<endl;
    else if(a==0)cout<<1<<endl<<c<<" "<<b<<endl;
    else cout<<2<<endl<<c<<" "<<b<<" "<<a<<endl;
    return 0;
}