The staple food in a fast food restaurant includes rice and steamed buns. The meat dishes include fish and braised pork. The vegetarian dishes include stir-fried green vegetables and green beans.
快餐店主食有米饭、馒头，荤菜有鱼、红烧肉，素菜有炒青菜、四季豆，快餐价格4元，只能荤菜和素菜各选一种，顾客一共有多少种选菜的方法．
<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<result>4</result>