- Get common words
- Calculate index sum using
`collections.Counter`

- Find the minimum
- Return result

```
def findRestaurant(self, l1, l2):
d = set(l1) & set(l2)
c = Counter({v: i + 1 for i, v in enumerate(l1) if v in d}) + \
Counter({v: i + 1 for i, v in enumerate(l2) if v in d})
res = min(c.values())
return [i for i, v in c.items() if v == res]
```