# -*- coding: utf-8 -*-

D = int(input())
a = list(map(int, input().split()))

for i in range(D, 2, -1):
    q = a[i]
    e = i - 3
    a[e+1] += q

d = min(2, D)
for i in range(d, -1, -1):
    d = i
    if a[i] != 0:
        break

print(d)
for i in range(d+1):
    if i==0:
        print(str(a[i]), end='')
    else:
        print(' '+str(a[i]), end='')
print()