Convert from didot point to sadzhen

Unit Definition (didot point)
The didot point is a unit of distance used in typography. It was named after the French typographer Firmin Didot (1764-1836).

Unit Definition (sadzhen)
The sadzhen is a traditional Russian unit of distance corresponding roughly to the English fathom and French toise. Early in the 1700s, Czar Peter the Great fixed the length of the sadzhen at exactly 7 English feet. This equals 3 arshin or 2.1336 meters. Sagene is an older transliteration of the Russian word.