d = int(input())
A = list(map(int, input().split()))
for i in range(d, 2, -1):
    A[i - 2] += A[i]
    A[i] = 0

while A and A[-1] == 0:
    A.pop()

if A:
    print(len(A) - 1)
    print(*A)
else:
    print(0)
    print(0)