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 | Walsall | 1–0 | Leicester City | 28 January 1978 |
| 2 | Nottingham Forest | 2–1 | Manchester City | 31 January 1978 |
| 3 | Bolton Wanderers | 1–0 | Mansfield Town | 6 February 1978 |
| 4 | Middlesbrough | 3–2 | Everton | 28 January 1978 |
| 5 | Derby County | 2–1 | Birmingham City | 1 February 1978 |
| 6 | Ipswich Town | 4–1 | Hartlepool United | 28 January 1978 |
| 7 | Newcastle United | 2–2 | Wrexham | 28 January 1978 |
| Replay | Wrexham | 4–1 | Newcastle United | 6 February 1978 |
| 8 | Bristol Rovers | 2–0 | Southampton | 28 January 1978 |
| 9 | West Ham United | 1–1 | Queens Park Rangers | 28 January 1978 |
| Replay | Queens Park Rangers | 6–1 | West Ham United | 31 January 1978 |
| 10 | Brighton & Hove Albion | 1–2 | Notts County | 31 January 1978 |
| 11 | Manchester United | 1–1 | West Bromwich Albion | 28 January 1978 |
| Replay | West Bromwich Albion | 3–2 | Manchester United | 1 February 1978 |
| 12 | Millwall | 4–0 | Luton Town | 31 January 1978 |
| 13 | Chelsea | 6–2 | Burnley | 31 January 1978 |
| 14 | Arsenal | 2–1 | Wolverhampton Wanderers | 28 January 1978 |
| 15 | Stoke City | 2–3 | Blyth Spartans | 6 February 1978 |
| 16 | Orient | 3–1 | Blackburn Rovers | 28 January 1978 |
Question:
What's the tie number when the away team was Mansfield Town?
Answer:
3.0