import           Control.Monad
import           Data.Char

parseLine :: String -> [[Int]]
parseLine line = [parseAssignment $ takeWhile (/= ',') line,
  parseAssignment $ drop 1 $ dropWhile (',' /= ) line]

parseAssignment :: String -> [Int]
parseAssignment assignment = do
  let first = takeWhile ('-' /=) assignment
  let second = drop 1 $  dropWhile ('-' /=) assignment
  [(read first)..  (read second)]


isIncluded :: [Int] -> [[Int]] -> Bool
isIncluded current list = any includes list
  where
    includes :: [Int] -> Bool
    includes range' = all (`elem` range') current

coveredByPartner :: [[Int]] -> Bool
coveredByPartner [first,second] = isIncluded first [second] ||  isIncluded second [first]


main = do
  input <- readFile "four-input.txt"
  let lists= (map (parseLine) $ lines input)
  print $ length $  filter id $  map coveredByPartner lists