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)

class Dictionary

	def initialize
		@table = []
	end

	def insert(e)
		i = 0
		loop do
			key = (hashcode(e) + i * hashcode2(e)) % SEED
			unless @table[key]
				@table[key] = e
				return self
			end
			i += 1
		end
	end

	def find(e)
		i = 0
		loop do
			key = (hashcode(e) + i * hashcode2(e)) % SEED
			if !@table[key]
				return false
			elsif @table[key] == e
				return true
			end
			i += 1
		end
	end

	private
	SEED = 16777219

	def hashcode(e)
		n = e.sum
		n % SEED
	end

	def hashcode2(e)
		n = e.sum
		1 + (n % (SEED - 1))
	end

end

n = STDIN.gets.to_i
dictionary = Dictionary.new
n.times do
	operation, parameter = STDIN.gets.split
	if operation == "insert"
		dictionary.send(operation, parameter)
	elsif operation == "find"
		found = dictionary.send(operation, parameter)
		puts(found ? "yes" : "no")
	else
		raise "Invalid input: #{operation}, #{parameter}"
	end
end