class A
  def initialize
    d = gets.chomp.to_i
    a = gets.chomp.split(' ').map(&:to_i).reverse

    0.upto(d-3) do |num|
      a[num+2] += a[num]
      a[num] = 0
    end

    if a.index{|i| i != 0}
      puts d - a.index{|i| i != 0}
    else
      puts 0
    end
    a.delete(0)
    puts (a.size.zero?)? 0 : a.reverse.join(' ')
  end
end

A.new