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 Scala (judge verdict: Time Limit Exceeded)

import scala.collection.mutable

object Main extends App {

  val sc = new java.util.Scanner(Console.in)

  def next() = sc.next()
  def nextInt() = next().toInt

  val n = nextInt()
  val input = Seq.fill(n)((next(), next()))

  var dict = mutable.Set[String]()

  for ((cmd, str) <- input) {
    cmd match {
      case "insert" => dict add str
      case "find"   => println(if (dict contains str) "yes" else "no")
    }
  }
}