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

b = b[::-1][:3]
if len(b) >= 3:
    if b[2] == 0:
        b.pop(-1)
        if b[1] == 0:
            b.pop(-1)
print(len(b) - 1)
print(*b)