Input:
angstroms [A] astronomical units [AU] barleycorns cables centimeters [cm] chains (surveyors') decimeters ells (UK) ems (pica) fathoms feet (UK and US) feet (US survey) furlongs hands hectometers inches kilometers [km] light years meters [m] micrometers miles (UK and US) miles (nautical) millimeters [mm] nanometers parsecs picometers yards