#include <bits/stdc++.h>
using namespace std;

const int64_t X = 1e18;

int main() {
    int n;
    cin >> n;
    vector<int64_t> b(n);
    for (int i = 0; i < n; i++) {
        scanf("%lld", &b[i]);
        if ((i + 1) / 2 % 2 == 1) {
            b[i] *= -1;
        }
    }
    for (int i = 1; i < n; i++) {
        b[i] += b[i - 1];
        if (abs(b[i]) > 2e18) {
            cout << -1 << endl;
            return 0;
        }
    }
    int64_t L = 1;
    int64_t R = X;
    for (int i = 0; i < n; i++) {
        if (i / 2 % 2 == 0) {
            L = max(L, -X + b[i]);
            R = min(R, -1 + b[i]);
        } else {
            L = max(L, 1 + b[i]);
            R = min(R, X + b[i]);
        }
    }
    if (L > R) {
        cout << -1 << endl;
        return 0;
    }
    vector<int64_t> a;
    a.push_back(L);
    for (int i = 0; i < n; i++) {
        if (i / 2 % 2 == 0) {
            a.push_back(-L + b[i]);
        } else {
            a.push_back(L - b[i]);
        }
    }
    cout << a.size() << endl;
    for (int i = 0; i <= n; i++) {
        cout << a[i] << endl;
    }
}