What is the last digit of the expression below?  $$\underbrace{2\times2\times2\times\cdots\times2}_{2017  ; 2s} \times \underbrace{3\times3\times3\times\cdots\times3}_{2017  ; 3s}$$ 
Overseas Competition->Knowledge Point->Calculation Modules->Whole Numbers->Calculation of Multi-digit Numbers