(* Enter your code here. Read input from STDIN. Print output to STDOUT *)
let makeList st =
  let rec mn st n sub xl =
    if (n < (String.length st)) then (
      if (st.[n] = ' ') then (mn st (n+1) "" (sub :: xl))
        else (mn st (n+1) (sub ^ (Char.escaped (st.[n]))) xl )
    )
      else (List.rev (sub :: xl))
  in mn st 0 "" []

let countList ll =
  let rec cn ll res xl =
    match ll with
    [] -> List.rev ( res :: xl )
    | fst :: rst -> (match res with
                    (a, b) -> if (fst = a) then cn rst (a, b+1) xl
                                else cn rst (fst, 1) (res :: xl) )
  in cn ll ("", 0) []

let searchMax ll =
  let rec sn ll res =
    match ll with
    [] -> res
    | (fa, fb) :: rst -> (match res with
                          (a, b) -> if (fb > b) then sn rst (fa, fb)
                                      else sn rst res)
  in sn ll ("", 0)

let printRes xl =
  match xl with
  (a, b) -> print_endline a

let main =
  let a = read_int ()
  and b = read_line () in
    makeList b |> List.sort compare |> countList |> searchMax |> printRes