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: Runtime Error)

object Main extends App {
  val src = io.Source.stdin.getLines.toList.tail.map(_.split(" ").toList).map { case List(cmd, key) => (cmd, key) }

  def judge(tupLi: List[(String, String)], keyLi: List[String], asrLi: List[String]): List[String] = tupLi match {
    case h :: tail if h._1 == "find" =>
      if (keyLi.exists(_ == h._2)) judge(tail, keyLi, "yes" :: asrLi)
      else judge(tail, keyLi, "no" :: asrLi)
    case h :: tail if h._1 == "insert" =>
      judge(tail, h._2 :: keyLi, asrLi)
    case Nil => asrLi.reverse
  }

  println(judge(src, Nil, Nil).mkString("\n"))
}