How many times in 24 hours a day the minute hand is perpendicular to the hour hand.
一天24小时中分针与时针垂直共有多少次．
<gadget id="calculator">24 - 2</gadget>
<output>22</output>

<gadget id="calculator">22 * 2</gadget>
<output>44</output>

<result>44</result>