gets
a = gets.chomp.split.map(&:to_i).reverse
(a.size-3).times do |i|
  a[i+2] += a[i]
  a[i] -= a[i]
end

a = a.reverse[0,4]
a.pop while a.last == 0 && a.size > 1

puts a.size-1
puts a.join(" ")