4 people conduct basketball training, passing and catching the ball to each other. Everyone is required to pass the ball to others immediately after receiving the ball. A serves the ball as the first pass. After the 6th pass, the ball returns to A’s hand. How many ways are there to pass the ball?
4个人进行篮球训练，互相传球接球，要求每个人接球后马上传给别人，开始由甲发球，并作为第一次传球，第6次传球后，球又回到甲手中，问有多少种传球方式？
<gadget id="calculator">6 - 1</gadget>
<output>5</output>

<gadget id="calculator">3 ** 5</gadget>
<output>243</output>

<result>243</result>