You are given an array of integers ai. Find the largest absolute value of difference between adjacent elements of the array max(abs(ai - ai + 1)).

Input

The only line of the input contains a list of space-separated integers ai (1 ≤ ai ≤ 100) — elements of the array. The size of the array is between 2 and 10, inclusive. Note that the size of the array is not given explicitly!

Output

Output a single integer — the largest absolute value of difference between adjacent elements of the array.

Examples

Input

2 10 4 8 6 12


Output

8


Input

3 3


Output

0

Source: codeforces | Difficulty: HARD


Solutions: