import Data.Bool
import Data.Char
import Data.Either
import Data.Function
import Data.List
import Data.Maybe
import Data.Ord
import Control.Applicative
import Control.Monad

import Data.Map (Map)
import qualified Data.Map as Map
import Data.Set (Set)
import qualified Data.Set as Set
import Data.Sequence (Seq)
import qualified Data.Sequence as Seq
import Data.Tree (Tree)
import qualified Data.Tree as Tree