let () =
  Scanf.scanf "%d\n" @@ fun t ->
  let xrr = Array.init t @@ fun _ -> Scanf.scanf "%d\n" @@ fun x -> x in
  let ans = ref true in
  for i = 0 to Array.length xrr - 1 do
    if i = 0 then
      if xrr.(0) = -1 || xrr.(0) = 1 then ans := !ans && true else ans := !ans && false
    else if abs(xrr.(i) - xrr.(i-1)) = 1 then ans := !ans && true
    else ans := !ans && false
  done;
  Printf.printf "%s\n" (if !ans then "T" else "F")