D = int(input())
A = [int(x) for x in input().split()]
if D>2:
    for i in range(3,D+1)[::-1]:
        A[i-2] += A[i]
if A[2] == 0:
    if A[1] == 0:
        print(0)
        print(A[0])
    else:
        print(1)
        print(''.join(str(item) + ' ' for item in A[0:2]))
else:
    print(2)
    print(''.join(str(item) + ' ' for item in A[0:3]))