#include "bits/stdc++.h"
using namespace std;
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define rer(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i))
#define reu(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))
static const int INF = 0x3f3f3f3f; static const long long INFL = 0x3f3f3f3f3f3f3f3fLL;
typedef vector<int> vi; typedef pair<int, int> pii; typedef vector<pair<int, int> > vpii; typedef long long ll;
template<typename T, typename U> static void amin(T &x, U y) { if(y < x) x = y; }
template<typename T, typename U> static void amax(T &x, U y) { if(x < y) x = y; }

int main() {
	int n;
	while(~scanf("%d", &n)) {
		vector<long long> b(n);
		for(int i = 0; i < n; ++ i)
			scanf("%lld", &b[i]);
		vector<pair<ll, int>> polys(n + 1);
		polys[0] = { 0, 1 };
		rep(i, n) {
			if(i % 2 == 0) {
				polys[i + 1] = { -polys[i].first + b[i], -polys[i].second };
			} else {
				polys[i + 1] = { polys[i].first - b[i], polys[i].second };
			}
		}
		const ll X = 1, Y = (ll)1e18;
		ll L = X, R = Y;
		rep(i, n + 1) {
			if(polys[i].second > 0) {
				amax(L, X - polys[i].first);
				amin(R, Y - polys[i].first);
			} else {
				amax(L, -Y + polys[i].first);
				amin(R, -X + polys[i].first);
			}
		}
		if(L > R) {
			puts("-1");
		} else {
			printf("%d\n", n + 1);
			for(int i = 0; i < n + 1; ++ i) {
				ll a = polys[i].second * L + polys[i].first;
				printf("%lld\n", a);
			}
		}
	}
	return 0;
}