Y=A+(B+C')'(A+B'+C)(A+B+C)
=A+(B'C)(A+B'+C)(A+B+C)
=A+(B'C)[(A+C)+(A+C)B'+(A+C)B+B'B]
=A+(B'C)(A+C)
=A+AB'C+B'C
=A+B'C