Sort Perm

We call a permutation$^{\dag}$ $P$ of length $N$ as $K$-sortable if it is possible to **sort** the permutation (in non-decreasing order) using the following operation **at most** once : - Choose a [subset](https://en.wikipedia.org/wiki/Subset) of indices from $[1, N]$; - Add $K$ to the elements present at all those indices in $P$. Given $N$ and a permutation $P$ of length $N$, find the **sum**