There are 8 episodes in a TV series, and it needs to be broadcast within 3 days, and at least one episode is broadcast every day, how many possible ways are there to arrange the broadcasting?
一部电视剧共8集，要在3天里播完，每天至少播一集，则安排播出的方法共有多少种可能．
<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">7 * 3</gadget>
<output>21</output>

<result>21</result>