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: Memory Limit Exceeded)

type Result = ([String], [Bool])

dictionary :: Result -> String -> Result
dictionary (items, found) input
  | cmd == "insert" = (insert target items, found)
  | cmd == "find"   = (items, (find target items) : found)
  where inputs = words input
        cmd    = inputs !! 0
        target = inputs !! 1

insert :: String -> [String] -> [String]
insert x [] = [x]
insert x (y:ys)
  | x `compare` y == GT = y : (insert x ys)
  | otherwise           = x:y:ys

find :: String -> [String] -> Bool
find x [] = False
find x (y:ys)
  | x == y    = True
  | otherwise = find x ys

main = do
  _ <- getLine
  inputs <- fmap lines getContents
  let result = foldl dictionary ([], []) inputs
  mapM_ putStrLn (map yesno $ reverse $ snd result)

yesno :: Bool -> String
yesno True = "yes"
yesno False = "no"