d=int(input())
a=list(map(int,input().split()))
a.reverse()
b=[1,0,-1,0]
for i in range(d-2):
  x=a[i]
  for j in range(4):
    a[i+j]-=x*b[j]
ans=[]
a.reverse()
for i in range(5):
  if a[i]==0:
    d2=i-1
    break
  else:
    ans.append(str(a[i]))
if d2==-1:
  print(0)
  print(0)
  exit()
print(d2)
print(' '.join(ans))