Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
|  | Country | Builder | Location | Ship | Class | Notes |
| --- | --- | --- | --- | --- | --- | --- |
| 23 January | United States | New York Shipbuilding Corporation | Camden, New Jersey | Salt Lake City | Pensacola-class cruiser |  |
| 12 April | France | Chantiers de la Gironde | Gironde | Commandant Teste | Seaplane carrier and tender |  |
| 25 April | United States | New York Navy Yard | Brooklyn, New York | Pensacola | Pensacola-class cruiser |  |
| 22 May | Japan | Uraga Dock | Uraga | Itsukushima | minelayer |  |
| 29 June | Germany | Deschimag Werk A.G | Bremen | Lichtenfels | heavy lift ship | For DDG Hansa |
| 3 July | United States | New York Shipbuilding Corporation | Camden, New Jersey | Chester | Northampton-class cruiser |  |
| 6 August | United Kingdom | Harland and Wolff | Belfast, Northern Ireland | Britannic | Ocean liner | For White Star Line |
| 5 September | United States | Fore River Shipyard | Quincy, Massachusetts | Northampton | Northampton-class cruiser |  |
| 7 September | United States | Newport News Shipbuilding & Dry Dock Company | Newport News, Virginia | Houston | Northampton-class cruiser |  |
| Date unknown | Norway | Trondhjems mekaniske Værksted | Trondheim | Barøy | Passenger/cargo ship |  |
| Date unknown | Germany | Deutsche Werft | Hamburg | Ceuta | Cargo ship | For Oldenburg-Portugiesische Dampfschiffs-Reederei |
| Date unknown | Germany | AG Weser | Bremen | Hercules | Cargo ship | For Dampfschiffahrts-Gesellschaft Neptun |
| Date unknown | United Kingdom | Smiths Dock Co Ltd | Middlesbrough | Vikingen I | Whaler |  |
| Date unknown | United Kingdom | Smiths Dock Co Ltd | Middlesbrough | Vikingen II | Whaler |  |
| Date unknown | United Kingdom | Smiths Dock Co Ltd | Middlesbrough | Vikingen III | Whaler |  |
| Date unknown | Sweden |  | Björkenäs, Sweden | Yngve | Schooner |  |
Question:
what are the total number of times northampton-class cruiser is listed as the class of the ship?
Answer:
3