Musical Rods

You have $N$ rods with you. The $i$-th rod has a length of $A_i$ and a beauty of $B_i$. You'd like to arrange these rods side-by-side in some order on the number line, starting from $0$. Let $x_i$ be the starting position of the $i$-th rod in an arrangement. The beauty of this arrangement is $$ \sum_{i=1}^N x_i\cdot B_i $$ What is the maximum beauty you can attain? Note that the left endpoin