using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;

class TEST{
	static void Main(){
		Sol mySol =new Sol();
		mySol.Solve();
	}
}

class Sol{
	public void Solve(){
		
		long lmin = 1;
		long rmax = (long)1e18;
		long l,r,c;
		
		l = lmin;
		r = rmax+1;
		while(r-l>0){
			c = (l+r)/2;
			long[] A = new long[N+1];
			A[0] = c;
			int of = 0;
			long sig = 1;
			for(int i=1;i<=N;i++){
				A[i] = (B[i-1]-A[i-1])*sig;
				if(A[i] > rmax){
					of = 1;
					break;
				}
				if(A[i] < lmin){
					of = -1;
					break;
				}
				sig *= -1;
			}
			//Console.WriteLine("c:{0},of:{1}",c,of);
			if(of == 0){
				Console.WriteLine(N+1);
				Console.WriteLine(String.Join("\n",A));
				return;
			}
			if(of == 1){
				l = c;
			}else{
				r = c;
			}
			
		}
		Console.WriteLine(-1);
	}
	int N;
	long[] B;
	public Sol(){
		N = ri();
		B = new long[N];
		for(int i=0;i<N;i++) B[i] = rl();
	}

	static String rs(){return Console.ReadLine();}
	static int ri(){return int.Parse(Console.ReadLine());}
	static long rl(){return long.Parse(Console.ReadLine());}
	static double rd(){return double.Parse(Console.ReadLine());}
	static String[] rsa(char sep=' '){return Console.ReadLine().Split(sep);}
	static int[] ria(char sep=' '){return Array.ConvertAll(Console.ReadLine().Split(sep),e=>int.Parse(e));}
	static long[] rla(char sep=' '){return Array.ConvertAll(Console.ReadLine().Split(sep),e=>long.Parse(e));}
	static double[] rda(char sep=' '){return Array.ConvertAll(Console.ReadLine().Split(sep),e=>double.Parse(e));}
}