Are you winnin' timmy?

Timmy Should Learn HOw to Use Loops

actually you don't need to loop using len(x)
you can use
for l in x:
to loop through all the characters of string x, with each charcter assigned to the varible "l"
while each loop instance

i made use of slice operator to remove first and last character

Use your middle school math
hint: sum of natural numbers upto n?

the easiest method for a beginner

This kind of kata help beginners like me to understand how careful one needed to solve realworld problems