#ifndef _GLIBCXX_NO_ASSERT
#include <cassert>
#endif
#include <cctype>
#include <cerrno>
#include <cfloat>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#if __cplusplus >= 201103L
#include <ccomplex>
#include <cfenv>
#include <cinttypes>
#include <cstdbool>
#include <cstdint>
#include <ctgmath>
#include <cwchar>
#include <cwctype>
#endif
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#if __cplusplus >= 201103L
#include <array>
#include <atomic>
#include <chrono>
#include <condition_variable>
#include <forward_list>
#include <future>
#include <initializer_list>
#include <mutex>
#include <random>
#include <ratio>
#include <regex>
#include <scoped_allocator>
#include <system_error>
#include <thread>
#include <tuple>
#include <typeindex>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#endif

using namespace std;
using i64 = int64_t;
using vi = vector<i64>;
using vvi = vector<vi>;
using i128 = __int128_t;

i128 get() {
    i64 a;
    cin >> a;
    return a;
}

void put(i128 a) {
    i64 b = i64(a);
    cout << b << endl;
}

int main() {
    int n;
    cin >> n;
    vector<i128> as;
    for (int i = 0; i < n; i++) {
        i128 a = get();
        as.push_back(a);
    }
    
    vector<i128> tmp;
    tmp.push_back(0);
    for (int i = 0; i < n; i++) {
        if (i % 2 == 0) {
            tmp.push_back(as[i] - tmp.back());
        } else {
            tmp.push_back(tmp.back() - as[i]);
        }
    }
    
    i128 mi = 1e30, t;
    for (int i = 0; i < n + 1; i++) {
        if (tmp[i] < mi) {
            mi = tmp[i];
            t = i % 4;
        }
    }
    
    i128 d = -mi + 1;
    for (int i = 0; i < n + 1; i++) {
        if (i % 4 == 0 || i % 4 == 3) {
            tmp[i] += d;
        } else {
            tmp[i] -= d;
        }
    }
    
    for (int i = 0; i < n + 1; i++) {
        if (tmp[i] <= 0 || tmp[i] > i128(1e9) * i128(1e9)) {
            cout << -1 << endl;
            return 0;
        }
    }
    
    cout << n + 1 << endl;
    for (int i = 0; i < n + 1; i++) {
        put(tmp[i]);
    }
}