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 Ruby (judge verdict: Time Limit Exceeded)

def add word
	val = hashFunc word
    val = (val + 1) % @dic.length while @dic[val]
    @dic[val] = word
end

def hashFunc word
	word.gsub!("A", "1")
	word.gsub!("C", "2")
	word.gsub!("G", "3")
	word.gsub!("T", "4")
    val = word.to_i % @dic.length
end

def find word
	val = hashFunc word
	while true
        return true if @dic[val] == word
        return false unless @dic[val]
        val = (val + 1) % @dic.length
    end
end

@dic = Array.new(4 ** 12)

n = gets.to_i
n.times{
	command, word = gets.chomp.split
	case command
	when "insert"
		add word
	else
		puts (find word) ? "yes" : "no"
	end
}