Please read the following table in HTML format from a webpage and then answer the question in detail according to the table. Each table cell is defined by a <td> and a </td> tag. Each table row starts with a <tr> and ends with a </tr> tag. 'rowspan=m' and 'colspan=n' represents a cell spaning over 'm' rows and 'n' columns.

Webpage title:
Akō Line
Table title:
Stations
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=2 > Common name </th><th colspan=1 rowspan=2 > Official line name </th><th colspan=1 rowspan=2 > Station </th><th colspan=1 rowspan=2 > Japanese </th><th colspan=1 rowspan=2 > Distance (km) </th><th colspan=1 rowspan=2 > Transfers </th><th colspan=2 rowspan=1 > Location </th></tr>
<tr> <th colspan=1 rowspan=1 > City </th><th colspan=1 rowspan=1 > Prefecture </th></tr>
<tr> <td colspan=1 rowspan=6 > A Sanyō Main Line </td><td colspan=1 rowspan=6 >  </td><td colspan=1 rowspan=1 > Himeji </td><td colspan=1 rowspan=1 > 姫路 </td><td colspan=1 rowspan=5 >  </td><td colspan=1 rowspan=1 > - </td><td colspan=1 rowspan=4 > Himeji </td><td colspan=1 rowspan=5 > Hyōgo </td></tr>
<tr> <td colspan=1 rowspan=1 > Agaho </td><td colspan=1 rowspan=1 > 英賀保 </td></tr>
<tr> <td colspan=1 rowspan=1 > Harima-Katsuhara </td><td colspan=1 rowspan=1 > はりま勝原 </td></tr>
<tr> <td colspan=1 rowspan=1 > Aboshi </td><td colspan=1 rowspan=1 > 網干 </td></tr>
<tr> <td colspan=1 rowspan=1 > Tatsuno </td><td colspan=1 rowspan=1 > 竜野 </td><td colspan=1 rowspan=1 > Tatsuno </td></tr>
<tr> <td colspan=1 rowspan=2 > Aioi </td><td colspan=1 rowspan=2 > 相生 </td><td colspan=1 rowspan=2 > 0.0 </td><td colspan=1 rowspan=2 > - </td><td colspan=1 rowspan=3 > Aioi </td><td colspan=1 rowspan=8 > Hyōgo </td></tr>
<tr> <td colspan=1 rowspan=4 > A Akō Line </td><td class="highlighted"  colspan=1 rowspan=20 > Akō Line </td></tr>
<tr> <td colspan=1 rowspan=1 > Nishi-Aioi </td><td colspan=1 rowspan=1 > 西相生 </td><td colspan=1 rowspan=1 > 3.0 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > Sakoshi </td><td colspan=1 rowspan=1 > 坂越 </td><td colspan=1 rowspan=1 > 7.8 </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=5 > Ako </td></tr>
<tr> <td colspan=1 rowspan=2 > Banshū-Akō </td><td colspan=1 rowspan=2 > 播州赤穂 </td><td colspan=1 rowspan=2 > 10.5 </td><td colspan=1 rowspan=1 > N Akō Line (for Okayama) </td></tr>
<tr> <td colspan=1 rowspan=16 > N Akō Line </td><td colspan=1 rowspan=1 > A Akō Line (for Himeji) </td></tr>
<tr> <td colspan=1 rowspan=1 > Tenwa </td><td colspan=1 rowspan=1 > 天和 </td><td colspan=1 rowspan=1 > 14.5 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > Bizen-Fukukawa </td><td colspan=1 rowspan=1 > 備前福河 </td><td colspan=1 rowspan=1 > 16.4 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > Sōgo </td><td colspan=1 rowspan=1 > 寒河 </td><td colspan=1 rowspan=1 > 19.6 </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=7 > Bizen </td><td colspan=1 rowspan=14 > Okayama </td></tr>
<tr> <td colspan=1 rowspan=1 > Hinase </td><td colspan=1 rowspan=1 > 日生 </td><td colspan=1 rowspan=1 > 22.1 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > Iri </td><td colspan=1 rowspan=1 > 伊里 </td><td colspan=1 rowspan=1 > 27.7 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > Bizen-Katakami </td><td colspan=1 rowspan=1 > 備前片上 </td><td colspan=1 rowspan=1 > 31.0 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > Nishi-Katakami </td><td colspan=1 rowspan=1 > 西片上 </td><td colspan=1 rowspan=1 > 32.3 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > Inbe </td><td colspan=1 rowspan=1 > 伊部 </td><td colspan=1 rowspan=1 > 34.5 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > Kagato </td><td colspan=1 rowspan=1 > 香登 </td><td colspan=1 rowspan=1 > 38.5 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > Osafune </td><td colspan=1 rowspan=1 > 長船 </td><td colspan=1 rowspan=1 > 42.3 </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=3 > Setouchi </td></tr>
<tr> <td colspan=1 rowspan=1 > Oku </td><td colspan=1 rowspan=1 > 邑久 </td><td colspan=1 rowspan=1 > 45.9 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > Odomi </td><td colspan=1 rowspan=1 > 大富 </td><td colspan=1 rowspan=1 > 48.0 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > Saidaiji </td><td colspan=1 rowspan=1 > 西大寺 </td><td colspan=1 rowspan=1 > 51.2 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > Ōdara </td><td colspan=1 rowspan=1 > 大多羅 </td><td colspan=1 rowspan=1 > 54.1 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=2 > Higashi-Okayama </td><td colspan=1 rowspan=2 > 東岡山 </td><td class="highlighted"  colspan=1 rowspan=2 > 57.4 </td><td colspan=1 rowspan=2 > S Sanyō Main Line </td></tr>
<tr> <td colspan=1 rowspan=4 >  </td></tr>
<tr> <td colspan=1 rowspan=4 > S Sanyō Main Line </td><td colspan=1 rowspan=1 > Takashima </td><td colspan=1 rowspan=1 > 高島 </td><td colspan=1 rowspan=3 > Okayama </td><td colspan=1 rowspan=3 > Okayama </td></tr>
<tr> <td colspan=1 rowspan=1 > Nishigawara </td><td colspan=1 rowspan=1 > 西川原 </td></tr>
<tr> <td colspan=1 rowspan=1 > 岡山 </td><td colspan=1 rowspan=1 > - </td></tr>
</table>
Question:
How long is the Ako Line?
Answer:
The entire 57.4-kilometre line is single track.