Convert from twain to bohr

Unit Definition (twain)
The 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.

Unit Definition (bohr)
The Bohr is a unit of distance commonly used in particle physics. It was named after the Danish physicist Niels Bohr (1885-1962), who explained the structure of atoms in a famous paper in 1913. The Bohr radius represents the mean distance between the proton and the electron in an unexcited hydrogen atom. It equals about 52.918 picometers (pm), or 52.918 x 10e-12 meter.