Maximum Pairwise Modular Sum

You are given an array $A$ containing $N$ integers, and a positive integer $M$. Find the maximum value of $$A_i + A_j + ((A_i - A_j) \bmod M)$$ across all pairs $1 \leq i, j \leq N$. Note that $x \bmod M$ refers to the smallest **non-negative** integer obtained as the remainder upon dividing $x$ by $M$. For example, $4 \bmod 3 = 1$ and $(-10) \bmod 3 = 2$. ### Input - The first line of input wi