Using operators for syms

Hi dear, I execute this program:

syms S;
A=1/(S+1);
B=2/(S+3);
Result=A+B

but result is:

Result =
1/(S + 1) + 2/(S + 3)

How can i change result to become format like below?

Result =
(3*S)/( S^2+4*S+3)