The school held a Maths and English test. $$10$$ students got an A in the Maths test while $$15$$ students got an A in the English test. $$2$$ students got an A in both the Maths test and the English test. How many students got an A in either test? 
Overseas Competition->Knowledge Point->Counting Modules->Inclusion-Exclusion Principle->Inclusion-Exclusion Principle for Two Sets