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: Accepted)

import Data.Hashable (hash)
import Data.Map (Map, empty, member, insert)
import Data.List (partition)
import Control.Monad (foldM_)

main :: IO ()
main = do
    getLine
    inputs <- fmap lines getContents :: IO [String]
    foldM_ solve empty inputs

solve :: Map Int String -> String -> IO (Map Int String)
solve dictionary input =
    if ope == 'i' then
        return $ insert key val dictionary
    else do
        if member key dictionary then
            putStrLn "yes"
        else
            putStrLn "no"
        return dictionary
  where
    val = last . words $ input
    key = hash val
    ope = head input