I need assistance on the below Python question:

Many documents use a specific format for a person's name. A program whose input is:

firstName middleName lastName

and whose output is:

lastName, firstInitial.middleInitial.

Ex: If the input is:

Pat Silly Doe 

the output is:

Doe, P.S. 

If the input has the form:

firstName lastName

the output is:

lastName, firstInitial.

Ex: If the input is:

Julia Clark 

the output is:

Clark, J. 

My code so far:

words = input().split()

if len(words) == 2:

print(words[1] + ', ' + words[0])

else:

print(words[2] + ', ' + words[0] + ' ' + words[1][0] + ',')

The output is only reflecting Doe, Pat S, but it should appear as Doe, P.S.