Convert from alen [Danish] to mark twain

Unit Definition (alen [Danish])
The Danish Alen (also used in Norway) is slightly longer than the Scandinavian Alen. It is just longer than two feet and more precisely equal to 62.77 centimeters (24.71 inches).

Unit Definition (mark twain)
The mark twain or twain is an old word for the number two, derived from the Anglo-Saxon twegen. The American author Samuel Clemens (1835-1910), who had been a riverboat pilot on the Mississippi in his youth, took his literary name from a traditional riverboat phrase "mark twain", meaning "exactly two" fathoms of water. This was the minimum depth needed for the boats to operate safely without running aground.