Maruko and her 4 friends are going on an outing. When taking pictures, one person must take pictures of the other 3 people. How many situations are there for taking pictures?
小丸子和她的朋友4个人去郊游，照相时必须有一个人给其她3个人拍照，共有多少种拍照情况．
<gadget id="calculator">4 * 3 * 2 * 1</gadget>
<output>24</output>

<result>24</result>