people stand in a row, including 4 boys and 3 girls. If the girls are not allowed to stand at both ends, and the girls stand together, there are several different ways to stand.
7个人站成一排，其中4名男生，3名女生，如果限定女生不站两头，且女生站在一起，一共有几种不同的站法．
<gadget id="calculator">4 * 3 * 2 * 1</gadget>
<output>24</output>

<gadget id="calculator">3 * 2 * 1</gadget>
<output>6</output>

<gadget id="calculator">24 * 3 * 6</gadget>
<output>432</output>

<result>432</result>