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)

{-# OPTIONS_GHC -O2 #-}

import qualified  Data.Map.Strict as Map

main = do
  n   <- readLn
  dictionary n Map.empty

dictionary n maps = do

-- Stop condition
  if n == 0 then return ()
  else do
    s' <- getLine
    let [fOI,str] = words s'

--Separate cases with find and insert
    if fOI == "find"
       then do
         putStrLn (findDic str maps)
         dictionary (n-1) maps
       else
         dictionary (n-1) (insertDic str maps)

--Because list is slow, use Data.Map
insertDic str maps = Map.insert str "yes" maps

--Corresponds when reference is not possible by using the lookup function
findDic   str maps
  | Map.lookup str maps == Nothing = "no"
  | otherwise                      = "yes"