Hi need help with this assignment in Compilers

Problem 2 - NFA and DFA Assume an alphabet with two symbols, s and r. 1. Draw the state transition graph of a DFA that accepts all strings over the alphabet that represents valid sequences of points in a single tennis game. A transition on input "s" means that the server won the point, and a transition on " r " means that the receiver won the point. Possible scores are 0/0,0/15,15/0,15/15,15/30,30/15,30/30,30/40,40/30, 0/30,0/40,30/0,40/0,15/40,40/15, deuce, advantage s, advantage r game. For example, your DFA should accept "s s s s" and "s r i r s r s r s r rH, 2. Build the minimal DFA, or show that your DFA in part 1 is already minimal