module StringSet = Set.Make (String)

let () =
  let n = int_of_string @@ read_line () in
  let ws = Array.init n @@ fun _ -> read_line () in
  let wss = Array.make (n + 1) StringSet.empty in
  for i = 0 to n - 1 do
    wss.(i + 1) <- StringSet.add ws.(i) wss.(i)
  done;
  print_endline @@
  if
    Array.fold_left ( && ) true @@
    Array.init (n - 1) @@ fun i ->
      not (StringSet.mem ws.(i + 1) wss.(i + 1)) && ws.(i).[String.length ws.(i) - 1] = ws.(i + 1).[0]
  then "Yes"
  else "No"
