require 'date'
a = Date.new(2015, 1, 1)
b = Date.new(2015, 12, 31)
count = 0
for i in a..b
  f_digit = i.day % 10
  s_digit = i.day / 10
  sum = f_digit + s_digit
  if i.month == sum
    count += 1
  end
end
puts count