I do understand, you want to eliminate the function keys - and I already showed you in the other thread a possible way to at least start off. You might want to build on that if you need something with additional capabilities.
What I don't understand is why you instead set off in another direction with this:
Do you realise that 0 + 59 gives 59? And do you also understand that the characters are represented internally as numeric values, so that character 59 (in the ASCII table) is the semicolon symbol ';'. So
is effectively the same as
a != ';'
Take a look at the ASCII table and see which characters are represented by the numbers 59 to 68 which you are trying to use.