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:
| Episode | First Air Date | Rating (18–49) | Share (18–49) | Viewers (millions) | Rank (timeslot) |
| --- | --- | --- | --- | --- | --- |
| 1.0 | January 5, 2009 | 3.1 | 8.0 | 8.74 | N/A |
| 2.0 | January 12, 2009 | 3.2 | 8.0 | 9.06 | N/A |
| 3.0 | January 19, 2009 | 3.6 | 9.0 | 9.95 | N/A |
| 4.0 | January 26, 2009 | 4.0 | 10.0 | 10.57 | N/A |
| 5.0 | February 2, 2009 | 4.1 | 10.0 | 11.02 | N/A |
| 6.0 | February 9, 2009 | 4.2 | 10.0 | 11.59 | N/A |
| 7.0 | February 16, 2009 | 4.4 | 10.0 | 12.52 | N/A |
| 8.0 | February 23, 2009 | 3.7 | 10.0 | 10.93 | N/A |
| 9.0 | March 2, 2009 | 5.4 | 13.0 | 15.48 | N/A |
| 10.0 | March 2, 2009 | 6.7 | 16.0 | 17.47 | N/A |
Question:
Name the total number of rank timeslot for 18-49 being 3.1
Answer:
1.0