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 OCaml (judge verdict: Memory Limit Exceeded)

let m = 33554432

let split str delim =
  let open String in
  let rec doit s acc =
    match
      try Some (rindex s delim) with _ -> None
    with
    | None -> s :: acc
    | Some i -> doit (sub s 0 i) (sub s (i + 1) (length s - i - 1) :: acc) in
  doit str []

let to_x = Array.make 128 0

let to_key s =
  let n = String.length s in
  let rec doit i acc =
    if i = n then acc
    else doit (i + 1) (4*acc + to_x.(Char.code s.[i])) in
  doit 0 1

let () =
  to_x.(Char.code 'A') <- 0;
  to_x.(Char.code 'C') <- 1;
  to_x.(Char.code 'G') <- 2;
  to_x.(Char.code 'T') <- 3;
  let n = read_int () in
  let t = Array.make m false in
  let rec doit i =
    if i < n then begin
      begin match split (read_line ()) ' ' with
      | ["insert"; s] -> t.(to_key s) <- true
      | ["find"; s] -> print_endline (if t.(to_key s) then "yes" else "no")
      | _ -> ()
      end;
      doit (i + 1)
    end in
  doit 0