import bisect
import copy
import decimal
import fractions
import heapq
import itertools
import math
import random
import sys
import time
from collections import Counter,deque,defaultdict
from functools import lru_cache,reduce
from heapq import heappush,heappop,heapify,heappushpop,_heappop_max,_heapify_max
def _heappush_max(heap,item):
    heap.append(item)
    heapq._siftdown_max(heap, 0, len(heap)-1)
def _heappushpop_max(heap, item):
    if heap and item < heap[0]:
        item, heap[0] = heap[0], item
        heapq._siftup_max(heap, 0)
    return item
from math import gcd as GCD
read=sys.stdin.read
readline=sys.stdin.readline
readlines=sys.stdin.readlines
write=sys.stdout.write
#import pypyjit
#pypyjit.set_param('max_unroll_recursion=-1')
#sys.set_int_max_str_digits(10**9)

N=int(readline())
A=[(0,1)]
for i in range(N):
    b=int(readline())
    x0,x1=A[-1]
    if i%2:
        A.append((x0-b,x1))
    else:
        A.append((-x0+b,-x1))
inf=1<<60
l,r=-inf,inf
for x0,x1 in A:
    if x1==1:
        l=max(l,1-x0)
        r=min(r,10**18-x0+1)
    else:
        l=max(l,x0-10**18)
        r=min(r,x0)
if l<r:
    x=l
    print(N+1)
    for x0,x1 in A:
        ans=x0+x1*x
        print(ans)
else:
    print(-1)