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:
| Name | Completed | Architect | Location | Year of listing & ref(s) |
| --- | --- | --- | --- | --- |
| 1 Booth Street | Circa 1850s | Unknown | Booth Street | 1974 |
| 8 Lower Park Road | circa 1875 | Alfred Waterhouse | Lower Park Road, Rusholme | 1974 |
| 29 Swan Street | circa 1865s | Unknown | Swan Street, Ancoats | 1989 |
| 46-48 Brown Street | 1868 | George Truefitt |  |  |
| 50 Newton Street | Circa 1900 | Clegg & Knowles | Newton Street, Piccadilly | 1988 |
| 53 King Street | 1912 | Charles Heathcote | King Street |  |
| 107 Piccadilly | 1899 | Charles Heathcote | Piccadilly | 1974 |
| 235-291 Deansgate | 1899 | Unknown | Deansgate | 1988 |
| Albert Hall | 1910 | W. J. Morley | Peter Street |  |
| Ancoats Hospital | 1891 | Lewis and Crawcroft | Ancoats | 1974 |
| Arkwright House | 1982 | Harry S. Fairhurst | Parsonage Gardens | 1982 |
| Apollo Theatre | 1930 | Unknown | Ardwick | 1994 |
| Barlow Hall | 15th century (altered since) | Unknown | Chorlton-cum-Hardy | 1974 (downgraded in 1994) |
| Barnes Hospital | 1875 | Lawrence Booth | Didsbury | 1998 |
| Bridgewater House | 1912 | Harry Fairhurst | Whitworth Street |  |
| Castlefield Congregational Chapel | 1858 | Edward Walters | Deansgate, Castlefield |  |
| CIS Tower | 1962 | Gordon Tait | Miller Street | 1995 |
| Chancellors Hotel & Conference Centre (The Firs) | 1851 | Edward Walters | Fallowfield | 1974 |
| Chancellors Hotel & Conference Centre (The Firs Gate Lodge) | 1851 | Edward Walters | Fallowfield | 1974 |
| Cooperative Press | Late 19th century | Unknown | Naples Street, Ancoats | 1994 |
| Corn Exchange | 1903 | Unknown | Exchange Square | 1973 |
| Canada House, Manchester | 1905 |  | Chepstow Street |  |
| Dalton Ellis Hall | 1882 | G. T. Redmayne | Conygham Road | 1974 |
| Derros Building | 1899 | William Sharpe | Great Ancoats Street | 1998 |
| Greenhayes Centre | 1896 | Unknown | Moss Side | 1994 |
| Hanover Building | 1909 | F.E.L Harris | Corporation Street | 1988 |
| Holyoake House | 1911 | F.E.L Harris | Dantzic Street | 1988 |
| National and Provoncial Building Society | Circa. 1910 | C. R. Cockerell | King Street | 1974 |
| New Century House | 1962 | G. S. Hay & Gordon Tait | Miller Street | 1995 |
| Manchester Deansgate railway station | 1896 | Unknown |  | 1998 |
| Manchester Opera House | 1912 | Richardson and Gill with Farquarson | Quay Street | 1974 |
| Manchester Oxford Road railway station | 1960 | W. R. Headley and Max Glendinning | Oxford Road | 1995 |
| Manchester Piccadilly station Store Street train shed | 1881 | Unknown | Piccadilly | 1994 |
| Manchester Victoria station | 1844 | Unknown | Hunts Bank | 1988 |
| Palace Theatre | 1891 | Alfred Derbyshire and F.Bennett Smith | Oxford Street | 1977 |
| The Ritz | 1927 | Unknown | Whitworth Street | 1994 |
| Royal Exchange | 1921 | Bradshaw, Gass & Hope | Cross Street |  |
| Redfern Building | 1936 | W. A. Johnson and J. W. Cooper | Dantzic Street | 1994 |
| Sackville Street Building | 1912 | Spalding and Cross | Sackville Street | 1974 |
| St. James Buildings | 1912 | Clegg, Fryer & Penman | 65-95 Oxford Street | 1988 |
| St Mary's Hospital | 1909 | John Ely | Wilmslow Road | 1994 |
| Samuel Alexander Building | 1919 | Percy Scott Worthington | Oxford Road | 2010 |
| Ship Canal House | 1927 | Harry S. Fairhurst | King Street | 1982 |
| Smithfield Market Hall | 1857 | Unknown | Swan Street, Ancoats | 1973 |
| Strangeways Gaol Gatehouse | 1868 | Alfred Waterhouse | Sherborne Street | 1974 |
| Strangeways Prison ventilation and watch tower | 1868 | Alfred Waterhouse | Sherborne Street | 1974 |
| Theatre Royal | 1845 | Irwin and Chester | Peter Street | 1974 |
| Toast Rack | 1960 | L. C. Howitt | Fallowfield | 1999 |
| The Old Wellington Inn | Mid-16th century | Unknown | Shambles Square | 1952 |
| Whitworth Park Mansions | Circa 1840s | Unknown | Whitworth Park | 1974 |
Question:
how many buildings had alfred waterhouse as their architect?
Answer:
3