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

#define show(x) cerr << #x << " = " << x << endl

using namespace std;
using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;

template <typename T>
ostream& operator<<(ostream& os, const vector<T>& v)
{
    os << "sz:" << v.size() << "\n[";
    for (const auto& p : v) {
        os << p << ",";
    }
    os << "]\n";
    return os;
}

template <typename S, typename T>
ostream& operator<<(ostream& os, const pair<S, T>& p)
{
    os << "(" << p.first << "," << p.second
       << ")";
    return os;
}


constexpr ll MOD = (ll)1e9 + 7LL;

template <typename T>
constexpr T INF = numeric_limits<T>::max() / 100;

// }}}

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);

    int n;
    cin >> n;
    vector<ll> b(n);
    for (int i = 0; i < n; i++) {
        cin >> b[i];
    }
    vector<bool> plus(n + 1);
    for (int i = 0; i <= n; i++) {
        plus[i] = (i % 4 == 0 or i % 4 == 3);
    }
    vector<ll> offset(n + 1);
    offset[0] = 0;
    for (int i = 1; i <= n; i++) {
        offset[i] = (i % 2 == 0) ? offset[i - 1] : -offset[i - 1];
        offset[i] += (i % 2 == 0) ? -b[i - 1] : b[i - 1];
    }

    constexpr ll MAX = (ll)1e18;
    ll lower = 1;
    ll upper = MAX;
    for (int i = 0; i <= n; i++) {
        if (plus[i]) {
            lower = max(lower, 1 - offset[i]);
            upper = min(upper, MAX - offset[i]);
        } else {
            lower = max(lower, offset[i] - MAX);
            upper = min(upper, offset[i] - 1);
        }
    }
    if (lower > upper) {
        cout << -1 << endl;
    } else {
        cout << n + 1 << endl;
        const ll a0 = lower;
        for (int i = 0; i <= n; i++) {
            cout << offset[i] + (plus[i] ? a0 : -a0) << endl;
        }
    }


    return 0;
}