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:
| Year | 1905–1911 | 1912–1915 | 1915–1918 | 1918–1921 |
| --- | --- | --- | --- | --- |
| chairperson | T.V. SivaraoPantulu | S. AdinarayanaRao | D. SankaraSastrulu | Shilpa Bendi |
| Year | 1921–1926 | 1926–1929 | 1929–1931 | 1931–1938 |
| chairperson | ChattiPurnayyaPantulu | M.V. Kamayyashetti | H. Suryanarayana | M.V. Ranganadham |
| Year | 1938–1942 | 1946–1949 | 1949–1952 | 1952–1956 |
| chairperson | ChallaNarasimhaNaidu | B.V. RamanayyaSetty | GynateVenkatarao | IppiliLaxminarayana |
| Year | 1956–1961 | 1962–1963 | 1963–1964 | 1967–1970 |
| chairperson | PasagadaSuryanarayana | MaturiRamarao | L. Suryalingam | M.A. Ravuf |
| Year | 1970–1972 | 1981–1992 | 1995–2000 | 2000–2005 |
| chairperson | IppiliVenkatarao | A.V. Narasimham (varam) | DudaBhavaniSankar | PaidisettiJayanthi |
| Year | 2005–present |  |  |  |
| ChairPerson | M.V. Padmavathi |  |  |  |
Question:
tell me the total number of chairpersons.
Answer:
21