#define _USE_MATH_DEFINES
#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<string>
#include<iostream>
#include<cctype>
#include<cstdio>
#include<vector>
#include<stack>
#include<queue>
#include <algorithm>
#include<math.h>
#include<set>
#include<map>
#include <sstream>
#include<iomanip>

//#include<bits/stdc++.h>


using namespace std;

int main() {
	int n;
	cin >> n;
	vector<int>x;
	for (int i = 0; i <= n; i++) {
		int a;
		cin >> a;
		x.push_back(a);
	}
	if (n<= 2) {
		for (int i = 0; i < n; i++) {
			if (i)cout << " ";
			cout << x[i];
		}cout << endl;
		return 0;
	}
	for (int i = n; i > 2; i--) {
		x[i - 2] += x[i];
	}
	for (int j = 2; j >= 0; j--) {
		if (x[j]) {
			cout << j << endl;
			for (int i = j; i >= 0; i--) {
				cout << x[i];
				if (i)cout << " ";
			}
			return 0;
		}
	}
	cout << 0 << endl << 0 << endl;

	
	return 0;
}