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: Wrong Answer)

def h(key)
  key.hash % 65535
end

class Dict
  def initialize
    @arr = []
  end
  def insert(s)
    @arr[h(s)] = s
  end
  def find(s)
    @arr[h(s)]
  end
end

n = STDIN.gets.to_i

dict = Dict.new
n.times.each {
  ss = STDIN.gets.split(' ')
  if ss[0] == 'insert' then
    dict.insert(ss[1])
  else
    if dict.find(ss[1]) then
      puts 'yes'
    else
      puts 'no'
    end
  end
}