Another system used to replace diacritics is the "x-system" ("x-sistemo" in Esperanto). The letter "x" is not used in the Esperanto alphabet, but it can be used to write diacritics. The x-system, unlike the h-system, does not treat ŭ differently from the other letters. For example, "ĝ" becomes "gx", "ĥ" becomes "hx" and "ŭ" becomes "ux". "flughaveno" remains the same, as there is no ambiguity.