Convert from gigaparsec to league [UK]

Unit Definition (gigaparsec)
The Gigaparsec is a non-metric unit of distance equal to one billion parsecs, 3.2616 billion light years, or 30.856 78 zettameters (30.856 78 x 1021 kilometers). The unit is used in astronomy.

Unit Definition (league [UK])
The league became a common unit of measurement throughout western Europe, although its length varied greatly from region to region. It was originally intended to represent the distance a person could walk in an hour. In many cases it was equal to 3 miles, (note that the definition of a mile also varied from region to region). At sea, the league was often equal to 3 nautical miles, which is 1/20 degree or 5556 meters (metres). In the USA and Great Britain, the league is defined to be 3 statute miles on land, or 3 nautical miles at sea.