Find the complement of the following expression and simplify it to have the minimum number of variables.

$f=A*B+C*D+A*C*D+C*D*(\frac{?}{\text{b}\text{a}\text{r}}(A)*B+A\frac{*}{b}ar(B))+B*D*(\frac{?}{\text{b}\text{a}\text{r}}(A)\frac{*}{b}ar(C)+A*C)$