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: Accepted)

import scala.io.StdIn
object Main extends App {
  val n = StdIn.readLine().trim.toInt
  val result = (0 until n).foldLeft(List.empty[String], Set.empty[String]){
      case ((acc, dict), _) =>
    val cmd = StdIn.readLine().split(' ')
    if(cmd(0) == "insert"){
      (acc, dict + cmd(1))
    } else {
      if(dict.contains(cmd(1))) {
        ("yes" :: acc, dict)
      } else {
        ("no" :: acc, dict)
      }
    }
  }

  println(result._1.reverse.mkString(f"%n"))

}