#include<bits/stdc++.h>

using namespace std;

typedef long long int64;
int64 RANGE = 1000000000000000000LL;


// A_0 A_1 A_2 A_3
//  B_0=A_1+A_2   A_2=B_0-A_1
//  B_1=A_2-A_3   A_3=A_2-B_1
//  B_2=A_3+A_4
//  B_3=A_4-A_5

int main()
{
  int N;
  int64 B[100000];

  cin >> N;
  for(int i = 0; i < N; i++) {
    cin >> B[i];
  }

  int64 initial = 1;
  set< int64 > fos;
  while(true) {
    int64 xs = initial;
    if(initial <= 0 || initial > RANGE || fos.count(initial)) {
      break;
    }
    fos.insert(initial);
    bool flag = false;
    for(int i = 0; i < N; i++) {
      if(i & 1) xs = xs - B[i];
      else xs = B[i] - xs;
      if(xs <= 0) {
        initial += -xs + 1;
        flag = true;
        break;
      }
      if(xs > RANGE) {
        initial -= xs + 1;
        flag = true;
        break;
      }
    }

    if(!flag) {
      cout << N + 1 << endl;
      int64 rev = initial;
      cout << rev << endl;
      for(int i = 0; i < N; i++) {
        if(i & 1) rev = rev - B[i];
        else rev = B[i] - rev;
        cout << rev << endl;
      }
      return (0);
    }


  }
  cout << -1 << endl;

}