#define _USE_MATH_DEFINES

#include <iostream>
#include <iomanip>

#include <algorithm>
#include <cmath>

#include <string>
#include <list>
#include <queue>
#include <vector>
#include <complex>
#include <set>

/////////
#define REP(i, x, n) for(int i = x; i < n; i++)
#define rep(i,n) REP(i,0,n)
#define P(p) cout<<(p)<<endl;
/////////
typedef long long LL;
typedef long double LD;
/////////
using namespace::std;
/////////

int A[10000];

int main(void){
    std::cin.tie(0); 
    std::ios::sync_with_stdio(false);
    std::cout << std::fixed;//
    //cout << setprecision(6);//
	
	int D;
	cin>>D;
	for(int i=0;i<=D;++i){
		cin>>A[i];
	}
	int kei = 0;
	for(int i=D;i>=3;--i){
		if(A[i] != 0){
			//kei = A[i];
			//A[i-2] = A[i-2] + kei;
			A[i-2] += A[i];
			A[i] = 0;
		}
	}
	int k;
	for(k=D;k>=0;--k){
		if(A[k] != 0){

			break;
		}
	}

	if(k<0){
		cout << "0\n0\n";
	}else{
		cout << k << "\n";
		for(int i= 0;i<=k;++i){
			cout << A[i];
			if(i<k){
				cout << " ";
			}else{
				cout << endl;
			}
		}

	}
	return 0;
}