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:
| # | Prime Minister | Date of birth | Start date\nof (first) term | Age at beginning\nof (first) term | End date\nof (final) term | Total time in\noffice | Date of death | Lifespan |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | Edmund Barton | 18 January 1849 | 1 January 1901 | 51 years, 348 days | 24 September 1903 | 996 days | 7 January 1920 | 25,920 days (70 years, 354 days) |
| 2 | Alfred Deakin | 3 August 1856 | 24 September 1903 | 47 years, 52 days | 29 April 1910 | 1,774 days | 7 October 1919 | 23,074 days (63 years, 65 days) |
| 3 | Chris Watson | 9 April 1867 | 27 April 1904 | 37 years, 18 days | 18 August 1904 | 113 days | 18 November 1941 | 27,251 days (74 years, 223 days) |
| 4 | George Reid | 25 February 1845 | 18 August 1904 | 59 years, 175 days | 5 July 1905 | 321 days | 12 September 1918 | 26,861 days (73 years, 199 days) |
| 5 | Andrew Fisher | 29 August 1862 | 13 November 1908 | 46 years, 76 days | 27 October 1915 | 1,758 days | 22 October 1928 | 24,160 days (66 years, 54 days) |
| 6 | Joseph Cook | 7 December 1860 | 24 June 1913 | 52 years, 199 days | 17 September 1914 | 450 days | 30 July 1947 | 31,645 days (86 years, 235 days) |
| 7 | Billy Hughes | 25 September 1862 | 27 October 1915 | 53 years, 32 days | 9 February 1923 | 2,662 days | 28 October 1952 | 32,905 days (90 years, 33 days) |
| 8 | Stanley Bruce | 15 April 1883 | 9 February 1923 | 39 years, 300 days | 22 October 1929 | 2,447 days | 25 August 1967 | 30,812 days (84 years, 132 days) |
| 9 | James Scullin | 18 September 1876 | 22 October 1929 | 53 years, 34 days | 6 January 1932 | 806 days | 28 January 1953 | 27,890 days (76 years, 132 days) |
| 10 | Joseph Lyons | 15 September 1879 | 6 January 1932 | 52 years, 113 days | 7 April 1939 | 2,648 days | 7 April 1939 | 21,753 days (59 years, 204 days) |
| 11 | Earle Page | 8 August 1880 | 7 April 1939 | 58 years, 242 days | 26 April 1939 | 19 days | 20 December 1961 | 29,718 days (81 years, 134 days) |
| 12 | Robert Menzies | 20 December 1894 | 26 April 1939 | 44 years, 127 days | 26 January 1966 | 6,735 days | 15 May 1978 | 30,461 days (83 years, 146 days) |
| 13 | Arthur Fadden | 13 April 1894 | 29 August 1941 | 47 years, 138 days | 7 October 1941 | 39 days | 21 April 1973 | 28,862 days (79 years, 8 days) |
| 14 | John Curtin | 8 January 1885 | 7 October 1941 | 56 years, 272 days | 5 July 1945 | 1,367 days | 5 July 1945 | 22,092 days (60 years, 178 days) |
| 15 | Frank Forde | 18 July 1890 | 6 July 1945 | 54 years, 353 days | 13 July 1945 | 7 days | 28 January 1983 | 33,796 days (92 years, 194 days) |
| 16 | Ben Chifley | 22 September 1885 | 13 July 1945 | 59 years, 294 days | 19 December 1949 | 1,620 days | 13 June 1951 | 24,004 days (65 years, 264 days) |
| 17 | Harold Holt | 5 August 1908 | 26 January 1966 | 57 years, 174 days | 19 December 1967 | 690 days | 17 December 1967 | 21,683 days (59 years, 134 days) |
| 18 | John McEwen | 29 March 1900 | 19 December 1967 | 67 years, 265 days | 10 January 1968 | 22 days | 20 November 1980 | 29,456 days (80 years, 236 days) |
| 19 | John Gorton | 9 September 1911 | 10 January 1968 | 56 years, 123 days | 10 March 1971 | 1,155 days | 19 May 2002 | 33,125 days (90 years, 252 days) |
| 20 | William McMahon | 23 February 1908 | 10 March 1971 | 63 years, 15 days | 5 December 1972 | 636 days | 31 March 1988 | 29,257 days (80 years, 37 days) |
| 21 | Gough Whitlam | 11 July 1916 | 5 December 1972 | 56 years, 147 days | 11 November 1975 | 1,071 days |  | 35,771 days (97 years, 342 days) |
| 22 | Malcolm Fraser | 21 May 1930 | 11 November 1975 | 45 years, 174 days | 11 March 1983 | 2,677 days |  | 30,709 days (84 years, 28 days) |
| 23 | Bob Hawke | 9 December 1929 | 11 March 1983 | 53 years, 92 days | 20 December 1991 | 3,206 days |  | 30,872 days (84 years, 191 days) |
| 24 | Paul Keating | 18 January 1944 | 20 December 1991 | 47 years, 336 days | 11 March 1996 | 1,543 days |  | 25,719 days (70 years, 151 days) |
| 25 | John Howard | 26 July 1939 | 11 March 1996 | 56 years, 229 days | 3 December 2007 | 4,284 days |  | 27,356 days (74 years, 327 days) |
| 26 | Kevin Rudd | 21 September 1957 | 3 December 2007 | 50 years, 73 days | 18 September 2013 | 1,017 days |  | 20,724 days (56 years, 270 days) |
| 27 | Julia Gillard | 29 September 1961 | 24 June 2010 | 48 years, 268 days | 27 June 2013 | 1,099 days |  | 19,255 days (52 years, 262 days) |
| 28 | Tony Abbott | 4 November 1957 | 18 September 2013 | 55 years, 318 days | Incumbent | 273 days |  | 20,680 days (56 years, 226 days) |
| # | Prime Minister | Date of birth | Start date\nof (first) term | Age at beginning\nof (first) term | End date\nof (final) term | Total time\nin office | Date of death | Lifespan |
Question:
how many prime ministers were born before 1850?
Answer:
2