d = int(input())
a = list(map(int, input().split()))
for i in range(d, 2, -1):
    a[i - 2] += a[i]
a = a[:3]
while a and a[-1] == 0:
    a.pop()
if not a:
    a.append(0)
d2 = len(a) - 1
print(d2)
print(*a)