<pre><code class="lang-python">class Solution:
 def numWaterBottles(self, numBottles: int, numExchange: int) -&gt; int:
 rem = numBottles 
 drunk = numBottles
 emptyBottles = numBottles

 while emptyBottles &gt;= numExchange:
 exchangedBottles = emptyBottles // numExchange
 emptyBottles = emptyBottles % numExchange
 drunk += exchangedBottles
 emptyBottles += exchangedBottles

 return drunk
</code></pre>

```python
class Solution:
    def numWaterBottles(self, numBottles: int, numExchange: int) -> int:
        rem = numBottles      
        drunk = numBottles
        emptyBottles = numBottles

        while emptyBottles >= numExchange:
            exchangedBottles = emptyBottles // numExchange
            emptyBottles = emptyBottles % numExchange
            drunk += exchangedBottles
            emptyBottles += exchangedBottles

        return drunk
        
```

518. Water Bottles