Georgetown Elementary School organized a competition for its students. Those attending it are divided into three categories-\/-Go, Checkers and Chess. A total of $42$ students participated in Go, $55$ in Checkers, and $33$ in Chess. There were $18$ students who participated in both Go and Checkers, $10$ in both Go and Chess, $9$ in both Checkers and Chess, and $5$ in all three groups. How many students are there in the competition? 
Overseas Competition->Knowledge Point->Counting Modules->Permutations and Combinations->Combinations Overseas Competition->Knowledge Point->Counting Modules->Inclusion-Exclusion Principle->Inclusion-Exclusion Principle for Three Sets