Lower upper problem

#1

it seems to be a simple one but when i wrote the code and compiled it is passing only 1 test case . what is wrong in the code ?

#2

I think the question says to print complete Invalid and not just I as well as complete UpperCase and not u.If it is not the error please let me know.

#4

okay there is no error you are right thanks :+1:

#5

Nice… Just mark the doubt as resolved.