Problem:
Search III

Your task is to write a program of a simple dictionary which implements the following instructions:

insert str: insert a string str in to the dictionary

find str: if the distionary contains str, then print 'yes', otherwise print 'no'

Input

In the first line n, the number of instructions is given. In the following n lines, n instructions are given in the above mentioned format.

Output

Print yes or no for each find instruction in a line.

Constraints

A string consists of 'A', 'C', 'G', or 'T'

1 ≤ length of a string ≤ 12

n ≤ 1000000

Sample Input 1

5
insert A
insert T
insert C
find G
find A

Sample Output 1

no
yes

Sample Input 2

13
insert AAA
insert AAC
insert AGA
insert AGG
insert TTT
find AAA
find CCC
find CCC
insert CCC
find CCC
insert T
find TTT
find T

Sample Output 2

yes
no
no
yes
yes
yes

Notes

Template in C

Solution in Haskell (judge verdict: Time Limit Exceeded)

import Control.Applicative
import Control.Monad
import Control.Monad.State
import Data.Map as M
type Dict a = M.Map a ()

main = do
  n <- readLn
  let dict = M.empty
  exec n dict

exec n d = evalStateT ( replicateM_ n $ do
                      [a,b] <- liftIO $ words<$>getLine
                      let command = toComm a b
                      command) d
toComm :: Ord a => String -> a -> StateT (Dict a) IO ()
toComm "insert" x = Main.insert x
toComm "find" x   = find x

insert :: Ord a => a -> StateT (Dict a) IO ()
insert x = modify (M.insert x ())

find :: Ord a => a -> StateT (Dict a) IO ()
find x = do
  ds <- get
  let res = M.lookup x ds
  if res == Nothing then liftIO $ putStrLn "no"
                    else liftIO $ putStrLn "yes"