9 students stand in two rows to take pictures, 4 in the front row and 5 in the back row, how many ways are there in total?
9名同学站成两排照相，前排4人，后排5人，共有多少种站法．
<gadget id="calculator">9 * 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1</gadget>
<output>362_880</output>

<result>362_880</result>