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:
| Stage | Date | Course | Distance | Winner | Race Leader |
| --- | --- | --- | --- | --- | --- |
| 1 | 10 May | Milan to Mantua | km (mi) | Learco Guerra ( ITA ) | Learco Guerra ( ITA ) |
| 2 | 11 May | Mantua to Ravenna | km (mi) | Learco Guerra ( ITA ) | Learco Guerra ( ITA ) |
| 3 | 13 May | Ravenna to Macerata | km (mi) | Alfredo Binda ( ITA ) | Alfredo Binda ( ITA ) |
| 4 | 15 May | Macerata to Pescara | km (mi) | Alfredo Binda ( ITA ) | Alfredo Binda ( ITA ) |
| 5 | 17 May | Pescara to Naples | km (mi) | Michele Mara ( ITA ) | Alfredo Binda ( ITA ) |
| 6 | 19 May | Naples to Rome | km (mi) | Ettore Meini ( ITA ) | Michele Mara ( ITA ) |
| 7 | 21 May | Rome to Perugia | km (mi) | Learco Guerra ( ITA ) | Luigi Marchisio ( ITA ) |
| 8 | 23 May | Perugia to Montecatini Terme | km (mi) | Learco Guerra ( ITA ) | Luigi Marchisio ( ITA ) |
| 9 | 25 May | Montecatini Terme to Genoa | km (mi) | Michele Mara ( ITA ) | Luigi Marchisio ( ITA ) |
| 10 | 27 May | Genoa to Cuneo | km (mi) | Luigi Giacobbe ( ITA ) | Luigi Giacobbe ( ITA ) |
| 11 | 29 May | Cuneo to Turin | km (mi) | Francesco Camusso ( ITA ) | Francesco Camusso ( ITA ) |
| 12 | 31 May | Turin to Milan | km (mi) | Ambrogio Morelli ( ITA ) | Francesco Camusso ( ITA ) |
| Total | Total | km (mi) | km (mi) | km (mi) | km (mi) |
Question:
What's the distance of the course of stage 4?
Answer:
km (mi)