Weird Modulo Problem

You are given an array $A$ of $N$ positive and pairwise distinct integers. You can permute the elements in any way you want. The cost of an ordering $(A_1, A_2, \ldots, A_N)$ is defined as $ (((A_1 \bmod A_2) \bmod A_3)......) \bmod A_N$ where $X \bmod Y$ means the remainder when $X$ is divided by $Y$. You need to find the maximum cost which can be attained through any possible ordering of the