Convert from marathon to league [nautical]

Unit Definition (marathon)
A long distance event based on an ancient Greek event, run over a distance of just over 26 miles.

Unit Definition (league [nautical])
The nautical league is approximately equal to three nautical miles, 1/20 degree, or 5556 meters (metres). Note that it is not equivalent to the portugese, french and spanish measurements of the league. The nautical league is also different from the league defined on land.