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 no. | Airdate | Dave Viewers | Dave Rank | Rank (cable) | Dave ja vu Viewers | Total viewers |
| --- | --- | --- | --- | --- | --- | --- |
| 1.0 | 4 October 2012 | 1978000.0 | 1.0 | 3.0 | 113000.0 | 2091000.0 |
| 2.0 | 11 October 2012 | 1567000.0 | 1.0 | 2.0 | 78000.0 | 1645000.0 |
| 3.0 | 18 October 2012 | 1519000.0 | 1.0 | 3.0 | 106000.0 | 1625000.0 |
| 4.0 | 25 October 2012 | 1345000.0 | 1.0 | 7.0 | 119000.0 | 1464000.0 |
| 5.0 | 1 November 2012 | 1561000.0 | 1.0 | 4.0 | 73000.0 | 1634000.0 |
Question:
Which episode number aired on 18 october 2012?
Answer:
3.0