Question: How many storeys does this tower house have which David Gregory inherited in 1664? 

Context articles: Tower castle
1600 Pennsylvania Avenue (TV series)
Kinnairdy Castle
Margaret's Castle
David Gregory (physician)
Blackcraig Castle
Craiglockhart Castle
Plague Town
Barscobe Castle
Parke's Castle

A tower castle is a small castle that mainly consists of a fortified tower or a tower-like structure that is built on natural ground.
 It is thus different from the motte-and-bailey castle, which it may resemble, but whose main defensive structure is built on a "motte" or artificial hill.
 The tower castle is occasionally also described as a tower house castle or a tower house.
1600 Pennsylvania Avenue is an MSNBC television program hosted by David Shuster that ended in 2009.
 The show is a panel discussion of news and trends in American politics among the panelists and anchor.
 It is a continuation of the show Race for the White House, which was originally hosted by David Gregory and aired in the same time slot from March to November 2008.
 Shuster became the host of the show when Gregory became moderator of NBC's "Meet the Press".
Kinnairdy Castle is a tower house, having five storeys and a garret, two miles south of Aberchirder, Aberdeenshire, Scotland.
 The alternative name is Old Kinnairdy.
Margaret's Castle is a castle in Ardglass, County Down, Northern Ireland.
 It is a small Tower house probably built in the 15th century.
 Only two storeys still exist but there is evidence that it was at least three storeys high.
 It is vaulted above the ground floor with a rectangular tower with projecting turrets in the north west wall.
 The doorway between the turrets was protected by a murder-hole.
 A spiral stairway rises within the west turret.
David Gregory (20 December 1625 – 1720) was a Scottish physician and inventor.
 His surname is sometimes spelt as Gregorie, the original Scottish spelling.
 He inherited Kinnairdy Castle in 1664.
 Three of his twenty-nine children became mathematics professors.
 He is credited with inventing a military cannon that Isaac Newton described as "being destructive to the human species".
 Copies and details of the model no longer exist.
 Gregory's use of a barometer to predict farming-related weather conditions led him to be accused of witchcraft by Presbyterian ministers from Aberdeen, although he was never convicted.
Blackcraig Castle is a tower house located at Blairgowrie, Perth, Scotland.
 Patrick Allan Fraser built the Bridge House this very unique building.
 The Bridge House is close to Blackcraig Castle which took almost 40 years to complete, from 1856 to late 1880s.
 Fraser bought the land in 1847 from trustees of Robert Rattray.
 The Castle became part of Hospitalfield Arts Trust after the death of Fraser in 1890.
 The Bridge House is run as a guest house.
 It is three storeys tall and it was built with lime-mortared rubble.
Craiglockhart Castle is a ruined tower house in the Craiglockhart district of Edinburgh, Scotland.
 It is situated in the Craiglockhart Campus of Edinburgh Napier University, to the north of Wester Craiglockhart Hill.
 Historic Scotland record that the tower was built by the Lockharts of Lee in the 15th century, although other sources state that it was the work of the Kincaid family during the 12th century.
 It was originally four storeys high, but now only the first and part of the second storey remain.
 The tower measures 8.7 by , and the walls are 1.5 m thick.
 The ruin is protected as a category B listed building, and as a scheduled monument.
Plague Town is a 2008 American horror film directed by David Gregory and written by David Gregory and John Cregan.
Barscobe Castle is a 17th-century tower house in Balmaclellan, Kirkcudbrightshire, Scotland.
 It is a typical house of a country laird, and according to a panel above the entrance, was built in 1648.
 The L-plan tower was constructed using stone taken from Threave Castle.
 The main block is three storeys high with the stair wing one storey higher.
 The gables have a modification of crowsteps found only in Galloway.
 It is a fine example of a mid-17th-century house which was unoccupied for many years until 1971 when it was restored.
 It has a modern byre (barn) attached, which has been converted into a garage.
 Barscobe Castle is a category A listed building.
Rising three storeys tall, in an idyllic setting on the banks of Lough Gill, in County Leitrim, Ireland, Parke’s Castle (also known as Newtown Castle) is a plantation era castle.
 In 1610 Robert Parke completed his fortified manor house on the site of an earlier fifteenth-century O'Rourke (Uí Ruairc) castle.
 He kept the walls of the original bawn - a spacious pentagonal defensive area - and demolished the O'Rourke tower house in the centre.
 The stones of O’Rourke’s tower were used to build the three-storey manor on the eastern side, eventually adorned with mullioned windows and diamond-shaped chimneys.