#include <iostream>
#include <string>
#include <queue>
#include <stack>
#include <algorithm>
#include <list>
#include <vector>
#include <complex>
#include <utility>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>
#include <bitset>
#include <ctime>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <cassert>
#include <cstddef>
#include <iomanip>
#include <numeric>
#include <tuple>
#include <sstream>
#include <fstream>
#include <chrono>
#include <random>

using namespace std;
#define REP(i, n) for (int (i) = 0; (i) < (n); (i)++)
#define FOR(i, a, b) for (int (i) = (a); (i) < (b); (i)++)
#define RREP(i, a) for(int (i) = (a) - 1; (i) >= 0; (i)--)
#define FORR(i, a, b) for(int (i) = (a) - 1; (i) >= (b); (i)--)
#define DEBUG(C) cerr << #C << " = " << C << endl;
using LL = long long;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<LL>;
using VVL = vector<VL>;
using VD = vector<double>;
using VVD = vector<VD>;
using PII = pair<int, int>;
using PDD = pair<double, double>;
using PLL = pair<LL, LL>;
using VPII = vector<PII>;
template<typename T> using VT = vector<T>;
#define ALL(a) begin((a)), end((a))
#define RALL(a) rbegin((a)), rend((a))
#define SORT(a) sort(ALL((a)))
#define RSORT(a) sort(RALL((a)))
#define REVERSE(a) reverse(ALL((a)))
#define MP make_pair
#define FORE(a, b) for (auto &&a : (b))
#define FIND(s, e) ((s).find(e) != (s).end())
#define EB emplace_back

const int INF = 1e9;
const int MOD = INF + 7;
const LL LLINF = 1e18;

int N;
VL a, b;
/*
idx % 4 == 0 || idx % 4 == 3 :++
            else          　　:--
*/
int main(void) {
    scanf("%d", &N);
    b.resize(N);
    a.resize(N + 1);
    for_each(ALL(b), [](LL &e){scanf("%lld", &e);});
    a[0] = 0;
    REP(i, N) {
        if ((i + 1) % 2) {
            a[i + 1] = b[i] - a[i];
        } else {
            a[i + 1] = a[i] - b[i];
        }
    }
    //REP(i, N + 1) cerr << a[i] << " ";cerr << endl;
    LL pma = 0, pmi = numeric_limits<LL>::max();
    LL mma = 0, mmi = numeric_limits<LL>::max();
    auto check = [](const int &idx) {
        return idx % 4 == 0 || idx % 4 == 3;
    };
    REP(i, N + 1) {
        if (check(i)) {
            pmi = min(pmi, a[i]);
        }
    }
    pmi *= -1;
    if (pmi >= 0) REP(i, N + 1) {
        if (check(i)) {
            a[i] += pmi + 1;
        } else {
            a[i] -= pmi + 1;
        }
    }
    
    REP(i, N + 1) {
        if (!check(i)) {
            mmi = min(mmi, a[i]);
        }
    }
    mmi *= -1;
    if (mmi >= 0) REP(i, N + 1) {
        if (check(i)) {
            a[i] -= mmi + 1;
        } else {
            a[i] += mmi + 1;
        }
    }
    
    REP(i, N + 1) {
        if (!check(i)) {
            mma = max(mma, a[i]);
        }
    }
    mma = mma - LLINF;
    if (mma > 0) REP(i, N + 1) {
        if (!check(i)) {
            a[i] += mma;
        } else {
            a[i] -= mma;
        }
    }
    
    REP(i, N + 1) {
        if (check(i)) {
            pma = max(pma, a[i]);
        }
    }
    pma = pma - LLINF;
    if (pma > 0) REP(i, N + 1) {
        if (!check(i)) {
            a[i] -= pma;
        } else {
            a[i] += pma;
        }
    }
    
    REP(i, N + 1) if (!(1 <= a[i] && a[i] <= LLINF)) {
        cout << -1 << endl;
        return 0;
    }
    cout << N + 1 << endl;
    for_each(ALL(a), [](LL &e){cout << e << endl;});
}