I would use Char.IsLetterOrDigit but I need the letters to be uppercase only.

I can't seem to find a way to combine Char.IsLetterOrDigit and Char.IsUpper because digits won't be allowed when I try this way:

`if (input.All(Char.IsLetterOrDigit) && input.All(Char.IsUpper))`

Am I missing something here?

How can I check each letter separately?