It is known that 4 empty bottles of mineral water can be exchanged for one bottle of mineral water. There are currently 16 empty bottles of mineral water. If you do not pay, how many bottles of mineral water can you drink at most.
已知4个矿泉水空瓶可以换矿泉水一瓶，现有16个矿泉水空瓶，若不交钱，最多可以喝矿泉水多少瓶．
<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<result>5</result>