#include <algorithm>
#include <cstdio>
#include <cstdlib>
#include <cctype>
#include <cmath>
#include <iostream>
#include <queue>
#include <list>
#include <stack>
#include <map>
#include <numeric>
#include <set>
#include <sstream>
#include <string>
#include <vector>
using namespace std;
#define REP(i,a,n) for(int i=(a); i<(int)(n); i++)
#define rep(i,n) REP(i,0,n)
#define FOR(it,c) for(__typeof((c).begin()) it=(c).begin(); it!=(c).end(); ++it)
#define ALLOF(c) (c).begin(), (c).end()
typedef long long ll;

int main(){
  ios::sync_with_stdio(false);
  int n;
  cin >> n;
  vector<ll> v;
  rep(i,n){
    ll a;
    cin >> a;
    v.push_back(a);
  }

  vector<ll> ret(n+1,0);
  ret[n] = 1;
  ll mn = ret[n], mx = ret[n];
  for(int i=n-1; i>=0; i--){
    if(i%2==0){
      ret[i] = v[i] - ret[i+1];
    }else{
      ret[i] = v[i] + ret[i+1];
    }
    mn = min(mn, ret[i]);
    mx = max(mx, ret[i]);
  }

  if(mn <= 0){
    ret[n] = -mn + 2;
    mn = ret[n];
    mx = ret[n];
    for(int i=n-1; i>=0; i--){
      if(i%2==0){
        ret[i] = v[i] - ret[i+1];
      }else{
        ret[i] = v[i] + ret[i+1];
      }
      mn = min(mn, ret[i]);
      mx = max(mx, ret[i]);
    }
  }

  if(mn <= 0 || mx > 1000000000000000000LL){
    cout << -1 << endl;
  }else{
    cout << n+1 << endl;
    rep(i,ret.size()){
      cout << ret[i] << endl;
    }
  }
  
  return 0;
}