let group_by cmp lst =
    let rec hdsplit hdval lst (lst1, lst2)  =
      if lst = [] then (lst1, lst2)
      else match cmp (List.hd lst) with
      | v when v = hdval -> hdsplit hdval (List.tl lst) ((List.hd lst):: lst1, lst2)
      | _ -> hdsplit hdval (List.tl lst) (lst1, (List.hd lst):: lst2)
    in
    let rec make_result lst result =
      match lst with
      | [] -> result
      | x::xs ->
          let lst1, lst2 = hdsplit (cmp x) lst ([], []) in
          make_result lst2 ((cmp x, lst1)::result)
    in
    make_result lst []

let judge_eto (lst: string list) =
    let glst = group_by (fun id -> id) lst in
    let rec get_max_length lst result =
        match lst with
        | [] -> result
        | x::xs ->
            let maxVal = max (List.length x) result in
            get_max_length xs maxVal
    in
    let elst = glst |> List.map (fun (_, lst) -> lst) in
    let mlen = get_max_length elst 0
    and ilen = List.length lst in
    int_of_float (ceil ((float_of_int ilen) /. 2.)) >= mlen
    
let () =
    let n = read_int ()
    and  elst = ref [] in
    for i = 1 to n do
        let line = read_line () in
        elst := line :: !elst
    done;
    (!elst) |> judge_eto |> (function | true -> "YES" | false -> "NO") |> (Printf.printf "%s\n")