I was scared of a hard combinatorial puzzle day, but this was a breeze.

{-# LANGUAGE TupleSections #-}
module Main (main) where
import Control.Monad ((<$!>))
import qualified Data.Text.IO as TextIO
import Data.Text (Text)
import qualified Data.Text as Text
import qualified Data.IntSet as IntSet
import Control.Arrow ((>>>))
import qualified Data.List as List
import qualified Data.IntMap as IntMap

part1 :: [IntSet.Key] -> IntSet.Key
part1 = IntSet.fromList
  >>> IntSet.foldl (+) 0

part2 :: [IntSet.Key] -> IntSet.Key
part2 = IntSet.fromList
  >>> IntSet.toAscList
  >>> take 20
  >>> sum

part3 :: [IntMap.Key] -> Int
part3 = List.map (, 1)
  >>> IntMap.fromListWith (+)
  >>> IntMap.toList
  >>> List.map snd
  >>> maximum

main :: IO ()
main = do
  sizes <- map (read . Text.unpack) . Text.split (== ',') <$!> TextIO.getLine
  print $ part1 sizes
  print $ part2 sizes
  print $ part3 sizes