#!/usr/bin/env python3
#fileencoding: utf-8

D = int(input())
a = [int(i) for i in input().strip().split(" ")]
a.reverse()
for i in range(D-2):
    a[i+2] += a[i]
    a[i] = 0

a.reverse()
D = 0
for i in range(len(a)):
    if a[i] != 0:
        D = i
print(D)
for i in range(D+1):
    print(a[i], end=" ")
print()