import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

D,*A = map(int,read().split())

A += [0,0,0,0,0]

A[1] += sum(A[3::2])
A[2] += sum(A[4::2])

A = A[:3]

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

if not A:
    print(0)
    print(0)
else:
    print(len(A) - 1)
    print(*A)