2. In $\triangle A B C$, the side lengths are $a=3, b=4, c=6, h_{a}$ is the length of the altitude from $a$, and $h_{b}, h_{c}$ have similar meanings. Then
$$
\left(h_{a}+h_{b}+h_{c}\right)\left(\frac{1}{h_{a}}+\frac{1}{h_{b}}+\frac{1}{h_{c}}\right)
$$

is equal to
2. $\frac{39}{4}$