#include <iostream>
using namespace std;
int main(){
	int d;	cin>>d;
	int a[d+1];
	for(int i=0;i<=d;i++)	cin>>a[i];
	int quo;
	for(int i=d;i>=3;i--){
		quo=a[i];	a[i]=0;
		a[i-2]+=quo;
	}
	int de=d;
	while(a[de]==0&&de>0)	de--;
	cout<<de<<endl;
	for(int i=0;i<=de;i++){
		if(i)	cout<<" ";
		cout<<a[i];
	}
	cout<<endl;
	return 0;
}