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:
| Game | Date | Team | Score | High points | High rebounds | High assists | Location Attendance | Series |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1.0 | April 19 | @ Indiana Pacers | W 103-100 | P. Pierce (40) | P. Pierce (11) | P. Pierce (6) | Conseco Fieldhouse | 1-0 |
| 2.0 | April 21 | @ Indiana Pacers | L 77-89 | A. Walker (19) | T. Battie (11) | P. Pierce (6) | Conseco Fieldhouse | 1-1 |
| 3.0 | April 24 | Indiana Pacers | W 101-83 | P. Pierce (21) | P. Pierce (12) | W. McCarty (6) | FleetCenter | 2-1 |
| 4.0 | April 26 | Indiana Pacers | W 102-92 | P. Pierce (37) | A. Walker (11) | P. Pierce (7) | FleetCenter | 3-1 |
| 5.0 | May 3 | @ Indiana Pacers | L 88-93 | A. Walker (21) | E. Williams (8) | P. Pierce (8) | Conseco Fieldhouse | 3-2 |
Question:
Name the number of high rebounds for april 21
Answer:
1.0