D. Maximal Difference
time limit per test
2 seconds
memory limit per test
64 megabytes
input
standard input
output
standard output

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