#include <iostream>
#include <vector>
#include <string>
#include <list>
#include <queue>
#include <algorithm>
#define rep(i, n) for(i = 0; i < (n); i++)
#define chmax(x, y) x = max(x, y)
#define chmin(x, y) x = min(x, y)
#define MOD 1000000007
#define PI 3.14159265358979323846
#define INF 1 << 30

using namespace std;
typedef long long ll;
typedef pair<int, int> pp;

int main(void) {
	int num, i, j, a;
	cin >> num;
	num++;
	vector<int> d(num);
	rep(i, num)
		cin >> d[i];
	reverse(d.begin(), d.end());
	rep(i, num - 3)
		d[i + 2] -= d[i];
	for (i = num - 3; i < num; i++) {
		if (d[i])
			break;
	}
	if (i == num)
		printf("0\n0\n");
	else
		cout << num - i - 1 << "\n";
	for (; i < num; i++) {
		cout << d[i];
		if (i < num - 1)
			printf(" ");
	}
	printf("\n");
	return 0;
}