#include <bits/stdc++.h>
using namespace std;
const long long m = 1000000000000000000;
int n; long long b[100009], a[100009];
int main() {
	scanf("%d", &n);
	for(int i = 0; i < n; i++) scanf("%lld", &b[i]);
	long long l = 1, r = m;
	for(int i = 0; i < n; i++) {
		if(i & 1) {
			l = max(1LL, l - b[i]);
			r = max(1LL, min(m, r - b[i]));
		}
		else {
			long long t = l;
			l = max(1LL, b[i] - r);
			r = max(1LL, min(m, b[i] - t));
		}
		//cout << l << ' ' << r << endl;
	}
	if(l > r) puts("-1");
	else {
		printf("%d\n", n + 1);
		for(int i = n; i >= 0; i--) {
			a[i] = l;
			if((i + 1) & 1) l += b[i - 1];
			else l = b[i - 1] - l;
		}
		for(int i = 0; i <= n; i++) printf("%lld\n", a[i]);
	}
	return 0;
}