This is the solution I have come up with but I’m unsure whether this is the best possible solution as far as Big (O) notation is concerned…

```
def solution(A):
B = [0, 0, 0, 0, 0]
for i in range (len(A)):
if A[i] == "Cardiology":
B[0] += 1
elif A[i] == "Neurology":
B[1] += 1
elif A[i] == "Orthopaedics":
B[2] += 1
elif A[i] == "Gynaecology":
B[3] += 1
elif A[i] == "Oncology":
B[4] += 1
max_patients = max(B)
return max_patients
```

### >Solution :

You can solve this very easily with `collections.Counter`

. You don’t want or need dictionaries, side lists or anything else extra. Everything you add is another thing to break. Keep it as simple as possible.

```
from collections import Counter
def solution(A):
return max(Counter(A).values())
```

I only stuck this in a function to give you context. There’s no reason for this to be a function. Wrapping this in a function is basically just giving the operation an alias. Unfortunately, your alias doesn’t give any indication of what you aliased. It’s better to just put the one line in place.