Stuck on a First Order Logic Proof

I am stuck on a proof:
R is serial, R is symmetric, and R is Euclidean, entails R is reflexive. This translates to: (for all x)(there exists a y)Rxy, (for all x)(for all y)(Rxy->Ryx),(for all x)(for all y)(for all z)((Rxy&Rxz)->Ryz) entails (for all x)Rxx

Please help! I don't understand how you can ever get to Rxx. I think I am missing some rule about substitution or universal introduction...