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:
| Tie no | Home team | Score | Away team | Date |
| --- | --- | --- | --- | --- |
| 1 | Darlington | 2–1 | Chester | 16 December 1978 |
| 2 | Barking | 1–2 | Aldershot | 16 December 1978 |
| 3 | Bury | 3–1 | Blackpool | 16 December 1978 |
| 4 | Watford | 1–1 | Southend United | 16 December 1978 |
| Replay | Southend United | 1–0 | Watford | 18 December 1978 |
| 5 | Crewe Alexandra | 0–1 | Hartlepool United | 16 December 1978 |
| 6 | Swindon Town | 3–0 | Enfield | 16 December 1978 |
| 7 | Doncaster Rovers | 0–3 | Shrewsbury Town | 16 December 1978 |
| 8 | Tranmere Rovers | 1–1 | Sheffield Wednesday | 16 December 1978 |
| Replay | Sheffield Wednesday | 4–0 | Tranmere Rovers | 19 December 1978 |
| 9 | Stockport County | 4–2 | Bradford City | 16 December 1978 |
| 10 | Barnsley | 1–1 | Rotherham United | 16 December 1978 |
| Replay | Rotherham United | 2–1 | Barnsley | 9 January 1979 |
| 11 | Maidstone United | 1–0 | Exeter City | 16 December 1978 |
| 12 | Portsmouth | 0–1 | Reading | 16 December 1978 |
| 13 | Carlisle United | 3–0 | Hull City | 16 December 1978 |
| 14 | Wimbledon | 1–1 | Bournemouth | 16 December 1978 |
| Replay | Bournemouth | 1–2 | Wimbledon | 28 December 1978 |
| 15 | Newport County | 0–0 | Worcester City | 16 December 1978 |
| Replay | Worcester City | 1–2 | Newport County | 18 December 1978 |
| 16 | York City | 3–0 | Scarborough | 16 December 1978 |
| 17 | Droylsden | 0–2 | Altrincham | 16 December 1978 |
| 18 | Leatherhead | 1–1 | Colchester United | 16 December 1978 |
| Replay | Colchester United | 4–0 | Leatherhead | 19 December 1978 |
| 19 | Swansea City | 2–2 | Woking | 16 December 1978 |
| Replay | Woking | 3–5 | Swansea City | 19 December 1978 |
| 20 | AP Leamington | 0–1 | Torquay United | 16 December 1978 |
Question:
What is the tie no for the away team altrincham?
Answer:
17.0