lines = File.read("day2").split("\n")
lines.pop

CHARS = ('a'..'z').to_a

def has_n?(string, n)
  CHARS.each do |c|
    return true if string.count(c) == n
  end
  return false
end

two = lines.count { |s| has_n?(s, 2) }
three = lines.count { |s| has_n?(s, 3) }
puts two * three