Why when I used "ch in ['A'..'Z'] or ['a'..'z']" I got WA while when
I used "ch in ['A'..'Z','a'..'z']" I got AC? Both worked well on my
computer.

Also, why are programms bigger now?

  Thanks for any help!

In Free Pascal your'll get error:
Error: Got "SET OF CHAR" expected "BOOLEAN"
(by the way:"SET OF CHAR" is the "['a'..'z']")
You should write "(ch in ['A'..'Z']) or (ch in ['a'..'z'])"

'Cause the Ural uses the FPC(Free Pascal Compliation)

"ch in ['A'..'Z','a'..'z']" = "(ch in ['A'..'Z'])or(ch in ['a'..'z'])"

Also you can do in such way:

...
if upcase(ch) in ['A'..'Z'] then
...