Suggestion to include test cases without spaces before punctuation marks, for example 'Hello world!' which would become elloHay orldway!. Most current (Python) solutions don't seem to cover this with the simple isalpha() check.

Hello! I believe the issue with your solution is in line 5: the = operator.

Your code would run the while loop once extra when p0 exactly equals p, so your n would be one greater than required in those cases.

Hope that helps!