let to_num s =
  let sym_to_num = function
    | 'A' -> 1
    | 'C' -> 2
    | 'G' -> 3
    | 'T' -> 4
    | _ -> exit 1
  in
  let n = String.length s in
  let rec doit i acc =
    if i = n then acc
    else doit (i + 1) (4*acc + sym_to_num s.[i])
  in
  doit 0 0

let () =
  let tbl = Array.make (22369620 + 1) false in
  let n = read_int () in
  let rec doit i =
    if i < n then begin
      match Scanf.scanf "%s %s\n" (fun x y -> x, y) with
      | ("insert", x) -> (tbl.(to_num x) <- true; doit (i + 1))
      | ("find", x) -> (print_endline (if tbl.(to_num x) then "yes" else "no"); doit (i + 1))
      | _ -> exit 1
    end
  in
  doit 0