Description

A long, linear field has N (1 <= N <= 1,000) clumps of grass at unique integer locations on what will be treated as a number line.Think of the clumps as points on the number line.

Bessie starts at some specified integer location L on the number line (1 <= L <= 1,000,000) and traverses the number line in the two possible directions (sometimes reversing her direction) in order to reach and eat all the clumps. She moves at a constant speed (one unit of distance in one unit of time), and eats a clump instantly when she encounters it.

Clumps that aren't eaten for a while get stale. We say the "staleness" of a clump is the amount of time that elapses from when Bessie starts moving until she eats a clump. Bessie wants to minimize the total staleness of all the clumps she eats.

Find the minimum total staleness that Bessie can achieve while eating all the clumps.

Input

* Line 1 : Two space-separated integers: N and L.

* Lines 2..N+1: Each line contains a single integer giving the position P of a clump (1 <= P <= 1,000,000).

Output

* Line 1: A single integer: the minimum total staleness Bessie can achieve while eating all the clumps.

4 10
1
9
11
19

44

Hint

INPUT DETAILS:

Four clumps: at 1, 9, 11, and 19. Bessie starts at location 10.

OUTPUT DETAILS: Bessie can follow this route:

• start at position 10 at time 0
• move to position 9, arriving at time 1
• move to position 11, arriving at time 3
• move to position 19, arriving at time 11
• move to position 1, arriving at time 29

  Source

  USACO 2005 November Gold