The 18 washed towels are hung on the rope. The two sides of each towel must be clamped with clips. The same clip can hold two adjacent towels. How many clips are used in total? How many
洗好的18条毛巾晾在绳上，每一块毛巾的两边必须用夹子夹住，同一个夹子可夹住相邻的两块毛巾，这样一共要用多少个夹子？多少
<gadget id="calculator">18 - 1</gadget>
<output>17</output>

<gadget id="calculator">17 * 1</gadget>
<output>17</output>

<gadget id="calculator">2 + 17</gadget>
<output>19</output>

<result>19</result>