import sys; input = sys.stdin.buffer.readline
sys.setrecursionlimit(10**7)
from collections import defaultdict
con = 10 ** 9 + 7; INF = float("inf")

def getlist():
	return list(map(int, input().split()))

#処理内容
def main():
	D = int(input())
	A = getlist()
	if D <= 2:
		print(D)
		print(*A)
		return

	for i in range(D - 2):
		a = A[-1 - i]
		A[-1 - i] = 0
		A[-3 - i] += a

	# print(A)
	if A[2] == 0:
		if A[1] == 0:
			if A[0] == 0:
				print(0)
				print(0)
			else:
				print(0)
				print(A[0])
		else:
			print(1)
			print(A[0], A[1])
	else:
		print(2)
		print(A[0], A[1], A[2])



if __name__ == '__main__':
	main()