In a cold drink shop, after drinking soda, you can exchange 2 empty bottles for 1 soda. Xiaofang bought 4 bottles of soda, how many bottles of soda can he drink at most?
一家冷饮店，喝完汽水后，用2个空瓶可以换1瓶汽水，小芳买了4瓶汽水，他最多能喝多少瓶汽水．
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">4 + 2 + 1 + 1</gadget>
<output>8</output>

<result>8</result>