Your university wants to build a new walkway, and they want
at least part of it to be covered. There are certain points
which must be covered. It doesnâ€™t matter if other points along
the walkway are covered or not.
The building contractor has an interesting pricing scheme.
To cover the walkway from a point at $x$ to a point at $y$, they will charge $c + (xy)^2$, where $c$ is a constant. Note that it is
possible for $x=y$. If so,
then the contractor would simply charge $c$.
Given the points along the walkway and the constant
$c$, what is the minimum
cost to cover the walkway?
Input
Input consists of a single test case. The test case will
begin with a line with two integers, $n$ ($1
\le n \le 1\, 000\, 000$) and $c$ ($1
\le c \le 10^{9}$), where $n$ is the number of points which must
be covered, and $c$ is the
contractorâ€™s constant. Each of the following $n$ lines will contain a single
integer, representing a point along the walkway that must be
covered. The points will be in order, from smallest to largest.
All of the points will be in the range from $1$ to $10^9$, inclusive.
Output
Output a single integer, representing the minimum cost to
cover all of the specified points. All possible inputs yield
answers which will fit in a signed $64$bit integer.
Sample Input 1 
Sample Output 1 
10 5000
1
23
45
67
101
124
560
789
990
1019

30726
