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 qualified Data.Map.Strict as Map

--only key map as dictionary
type Dictionary = Map.Map String ()

insert::Dictionary -> String -> Dictionary
insert dic x = Map.insert x () dic

find::Dictionary -> String -> Bool
find dic x = Map.member x dic


do_n::Dictionary -> Int -> IO()
do_n d 0 = return()
do_n d n = do
  order<-getLine
  let ord:v:[] = words order
  if ord == "insert" then do
    seq (insert d v) (do_n (insert d v) (n-1))
                     else do
    putStr (if (find d v) then "yes" else "no")
    putStr "\n"
    do_n d (n-1)

main::IO()
main = do
  nc<-getLine
  let n = read nc::Int
  do_n Map.empty n