require "date"

date = Date.new(2015, 1, 1)
count = 0

1.upto(12) do |month|
  date = date.next_month

  1.upto(date.prev_day.day) do |day|
    if month == day.to_s.chars.map(&:to_i).reduce(&:+)
      count += 1
    end
  end
end

p count