A) How large can the boolean expression be? Where are no restrictions about the first line in the statement.
B) Is it necessary to optimize the expression? Or we can just read it in reverse polish manner and use without worrying about TLE?

I didn't do any optimizations - just what I have invented by myself without thinking hard - and got AC 0.015.

Got AC with 0.001 sec from the first try. I used Bauer algo (You can read about it at algolist.manual.ru). What was Your idea?