There are 4 phalanxes in total, each phalanx has 15 rows, and each row has 15 people. How many people participated in the performance?
秋季运动会进行大型团体操表演，一共有4个方阵，每个方阵有15行，每行有15人，一共有多少人参加表演？
<gadget id="calculator">15 * 15 * 4</gadget>
<output>900</output>

<result>900</result>