REGEX, How to select based on 2 conditions

I have the following 3 lines:

CO2_Max
Max_CO2
CO2_Max_SP

I use python and I want a regex pattern that selects the first 2 lines and ignores the third one.
( contains the word ‘Max’ and does not end with ‘SP’ ).

I tried the following pattern

".*Max.*[^SP]"

This selected the 3 lines.. and third line was selected like CO2_Max_ SP

And the following pattern

".*Max.*[^SP]$"

Returned only the second line for some reason
Any ideas how to make this work as intended?

>Solution :

You need to use a negative lookbehind. Try this: ^.*Max.*(?<!SP)$

Test here: https://regex101.com/r/sVvpj1/1

import re

s = """CO2_Max
Max_CO2
CO2_Max_SP"""

regex = re.compile(r'^.*Max.*(?<!SP)$', re.M)
l = regex.findall(s)

print(l)
# ['CO2_Max', 'Max_CO2']

Explanation:

^           matches the start of line
.*Max.*     matches anything till and after 'Max'
(?<!SP)$    ensures that the line does not end with 'SP'