D = int(input())
A = list(map(int,input().split()))
B = [1,0,-1,0]
if D<3:
    print(D)
    print(*A)
else:
    A = A[::-1]
    for i in range(D-4+2):
        a = A[i]
        for j in range(4):
            A[i+j] -= a*B[j]
    ind = -1
    for i in range(D+1):
        if A[i]!=0:
            ind = i
            break
    if ind==-1:
        print(0)
        print(0)
    else:
        print(D-ind)
        print(*A[ind:][::-1])