#include <iostream>
#include <vector>
#include <cstdio>
#include <sstream>
#include <map>
#include <string>
#include <algorithm>
#include <queue>
#include <cmath>
#include <functional>
#include <set>
#include <ctime>
#include <random>
#include <chrono>
#include <cassert>
#include <tuple>
#include <utility>
using namespace std;

namespace {
  using Integer = long long; //__int128;
  template<class T, class S> istream& operator >> (istream& is, pair<T,S>& p){return is >> p.first >> p.second;}
  template<class T> istream& operator >> (istream& is, vector<T>& vec){for(T& val: vec) is >> val; return is;}
  template<class T> istream& operator ,  (istream& is, T& val){ return is >> val;}
  template<class T, class S> ostream& operator << (ostream& os, const pair<T,S>& p){return os << p.first << " " << p.second;}
  template<class T> ostream& operator << (ostream& os, const vector<T>& vec){for(size_t i=0; i<vec.size(); i++) os << vec[i] << (i==vec.size()-1?"":" "); return os;}
  template<class T> ostream& operator ,  (ostream& os, const T& val){ return os << " " << val;}

  template<class H> void print(const H& head){ cout << head; }
  template<class H, class ... T> void print(const H& head, const T& ... tail){ cout << head << " "; print(tail...); }
  template<class ... T> void println(const T& ... values){ print(values...); cout << endl; }

  template<class H> void eprint(const H& head){ cerr << head; }
  template<class H, class ... T> void eprint(const H& head, const T& ... tail){ cerr << head << " "; eprint(tail...); }
  template<class ... T> void eprintln(const T& ... values){ eprint(values...); cerr << endl; }

  class range{ Integer start_, end_, step_; public: struct range_iterator{ Integer val, step_; range_iterator(Integer v, Integer step) : val(v), step_(step) {} Integer operator * (){return val;} void operator ++ (){val += step_;} bool operator != (range_iterator& x){return step_ > 0 ? val < x.val : val > x.val;} }; range(Integer len) : start_(0), end_(len), step_(1) {} range(Integer start, Integer end) : start_(start), end_(end), step_(1) {} range(Integer start, Integer end, Integer step) : start_(start), end_(end), step_(step) {} range_iterator begin(){ return range_iterator(start_, step_); } range_iterator   end(){ return range_iterator(  end_, step_); } };

  inline string operator "" _s (const char* str, size_t size){ return move(string(str)); }
  constexpr Integer my_pow(Integer x, Integer k, Integer z=1){return k==0 ? z : k==1 ? z*x : (k&1) ? my_pow(x*x,k>>1,z*x) : my_pow(x*x,k>>1,z);}
  constexpr Integer my_pow_mod(Integer x, Integer k, Integer M, Integer z=1){return k==0 ? z%M : k==1 ? z*x%M : (k&1) ? my_pow_mod(x*x%M,k>>1,M,z*x%M) : my_pow_mod(x*x%M,k>>1,M,z);}
  constexpr unsigned long long operator "" _ten (unsigned long long value){ return my_pow(10,value); }

  inline int k_bit(Integer x, int k){return (x>>k)&1;} //0-indexed

  mt19937 mt(chrono::duration_cast<chrono::nanoseconds>(chrono::steady_clock::now().time_since_epoch()).count());

  template<class T> string join(const vector<T>& v, const string& sep){ stringstream ss; for(size_t i=0; i<v.size(); i++){ if(i>0) ss << sep; ss << v[i]; } return ss.str(); }

  inline string operator * (string s, int k){ string ret; while(k){ if(k&1) ret += s; s += s; k >>= 1; } return ret; }
}
constexpr long long mod = 9_ten + 7;

int main(){
  int n;
  cin >> n;
  vector<long long> v(n);
  cin >> v;

  if(n == 1){
    if(v[0] > 1){
      println(n+1);
      println(1);
      println(v[0]-1);
      return 0;
    }else{
      println(-1);
      return 0;
    }
  }

  vector<__int128> a(n+1);
  for(int i=1; i<=n; i++){
    if(i%2){
      a[i] = -a[i-1] + v[i-1];
    }else{
      a[i] = +a[i-1] - v[i-1];
    }
  }
  vector<__int128> wa(2, 18_ten + 10);
  vector<__int128> wb(2, -1);
  for(int i=0; i<n+1; i++){
    if(i%4 == 0 || i%4 == 3){
      wa[0] = min(wa[0], a[i]);
      wb[0] = max(wb[0], a[i]);
    }else{
      wa[1] = min(wa[1], a[i]);
      wb[1] = max(wb[1], a[i]);
    }
  }


  __int128 a0 = 1;

  int t = 0;
  
  while(1){
    __int128 x = min( wa[0] + a0, wa[1] - a0);
    __int128 y = max( wb[0] + a0, wb[1] - a0);

    if(y >= v[0]){
      println(-1);
      return 0;
    }

    if(t>1000000){
      println(-1);
      return 0;
    }

    if(x <= 0){
      a0 = -x + 1;
      continue;
    }

    break;
  }

  a[0] = a0;
  for(int i=1; i<=n; i++){
    if(i%2){
      a[i] = -a[i-1] + v[i-1];
    }else{
      a[i] = +a[i-1] - v[i-1];
    }
  }

  for(int i=0; i<n; i++){
    if(i%2==0) assert(a[i]+a[i+1] == v[i]);
    else assert(a[i]-a[i+1] == v[i]);
  }

  println(n+1);
  for(int i=0; i<=n; i++){
    println((long long)(a[i]));
  }



  return 0;
}