#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <cassert>
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;
typedef __int128_t lll;
const ll MAX=1e18;
const ll MIN=1;
int main()
{
	int n; cin>>n;
	ll b[100001];
	for(int i=0; i<n; i++) cin>>b[i];
	int p[100001]; lll a[100001];
	p[0]=1, a[0]=0;
	for(int i=0; i<n; i++){
		if(i&1){
			p[i+1]=p[i];
			a[i+1]=a[i]-b[i];
		}else{
			p[i+1]=-p[i];
			a[i+1]=b[i]-a[i];
		}
	}
	lll l=MIN, r=MAX;
	for(int i=1; i<=n; i++){
		if(p[i]==1){
			l=max(l, MIN-a[i]);
			r=min(r, MAX-a[i]);
		}else{
			l=max(l, a[i]-MAX);
			r=min(r, a[i]-MIN);
		}
	}
	if(l>r){
		cout<<-1<<endl;
	}else{
		cout<<n+1<<endl;
		for(int i=0; i<=n; i++){
			if(p[i]==1) cout<<(ll)(l+a[i])<<endl;
			else cout<<(ll)(-l+a[i])<<endl;
		}
	}
	return 0;
}