As implemented on the mechanical typewriter, the keyboard contained a single dead key, with the acute accent in the lowercase position, and the diaeresis in the uppercase position. With these, one could write , , , , , and . A separate key provided . (A dead key "~" is used on the Spanish and Portuguese keyboards, but on the Latin American keyboard the "~" is not a dead key). The inverted marks and completed the required minimum. When an additional key was added to electro-mechanical typewriters, this was used for and , though these are not required. (They are somewhat archaic ordinal abbreviations: for "primero", for "segunda", etc.)