Please help me design this Deterministic finite automaton. Thanks!

4. (10 pts) Design a minimum DFA for the following language, and describe the strings corresponding to each state. L = {w over {a,b} I nab(w) = nba(u)} where nab(w) is the number of occurrences of substring ab in string w and nba() is the number of occurrences of substring ba in string w. For example, string e is in the language, because nab(e) = nba(c) = 0, String baaaabb is in the language, because nab(baaaabb) = 1 and nba (baaaalb) = 1. String aaabaaaab is not in the language, because nab(aaabaaaab) = 2 but nba (aaabaaa(b) = 1