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:
XVIII Reserve Corps (German Empire)
Table title:
Structure on formation
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=1 > Corps </th><th colspan=1 rowspan=1 > Division </th><th colspan=1 rowspan=1 > Brigade </th><th colspan=1 rowspan=1 > Units </th></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=21 > XVIII Reserve Corps </td><td colspan=1 rowspan=9 > 21st Reserve Division </td><td colspan=1 rowspan=2 > 41st Reserve Infantry Brigade </td><td colspan=1 rowspan=1 > 80th Reserve Infantry Regiment </td></tr>
<tr> <td colspan=1 rowspan=1 > 87th Reserve Infantry Regiment </td></tr>
<tr> <td colspan=1 rowspan=2 > 42nd Reserve Infantry Brigade </td><td colspan=1 rowspan=1 > 81st Reserve Infantry Regiment </td></tr>
<tr> <td colspan=1 rowspan=1 > 88th Reserve Infantry Regiment </td></tr>
<tr> <td colspan=1 rowspan=5 >  </td><td colspan=1 rowspan=1 > 7th Reserve Dragoon Regiment </td></tr>
<tr> <td colspan=1 rowspan=1 > 21st Reserve Field Artillery Regiment </td></tr>
<tr> <td colspan=1 rowspan=1 > 4th Company, 11th Pioneer Battalion </td></tr>
<tr> <td colspan=1 rowspan=1 > 21st Reserve Divisional Pontoon Train </td></tr>
<tr> <td colspan=1 rowspan=1 > 17th Reserve Medical Company </td></tr>
<tr> <td colspan=1 rowspan=10 > 25th Reserve Division </td><td colspan=1 rowspan=2 > 49th Reserve Infantry Brigade </td><td colspan=1 rowspan=1 > 116th Reserve Infantry Regiment </td></tr>
<tr> <td colspan=1 rowspan=1 > 118th Reserve Infantry Regiment </td></tr>
<tr> <td colspan=1 rowspan=2 > 50th Reserve Infantry Brigade </td><td class="highlighted"  colspan=1 rowspan=1 > 168th Infantry Regiment </td></tr>
<tr> <td colspan=1 rowspan=1 > 83rd Reserve Infantry Regiment </td></tr>
<tr> <td colspan=1 rowspan=6 >  </td><td colspan=1 rowspan=1 > 4th Reserve Dragoon Regiment </td></tr>
<tr> <td colspan=1 rowspan=1 > 25th Reserve Field Artillery Regiment </td></tr>
<tr> <td colspan=1 rowspan=1 > 1st Reserve Company, 11th Pioneer Battalion </td></tr>
<tr> <td colspan=1 rowspan=1 > 2nd Reserve Company, 11th Pioneer Battalion </td></tr>
<tr> <td colspan=1 rowspan=1 > 25th Reserve Divisional Pontoon Train </td></tr>
<tr> <td colspan=1 rowspan=1 > 18th Reserve Medical Company </td></tr>
<tr> <td colspan=1 rowspan=2 > Corps Troops </td><td colspan=1 rowspan=2 >  </td><td colspan=1 rowspan=1 > 18th Reserve Telephone Detachment </td></tr>
<tr> <td colspan=1 rowspan=1 > Munition Trains and Columns corresponding to the III Reserve Corps </td></tr>
</table>
Question:
How many Infantry Regiments were included in the XVIII Reserve Corps, and what is the number of the regiment?
Answer:
XVIII Reserve Corps included one Infantry Regiment (168th).