Maximum Perfection Index

You are given an array of n integers. The perfection index of an array is defined as the sum of the absolute differences between consecutive elements. In other words, for an array a[0], a[1], …, a[n-1], its perfection index is given by:

\(\sum_{i=1}^{n-1} |a[i] - a[i-1]|\)

Your task is to compute and print the perfection index of the given array.

Example:

Input:
5
1 3 2 4 7
Output:
8

</p>

In the above example, the differences are: |3-1| = 2, |2-3| = 1, |4-2| = 2, |7-4| = 3 so the perfection index is 2+1+2+3 = 8.

inputFormat

The first line contains a single integer n representing the number of elements in the array. The second line contains n space-separated integers.

outputFormat

Output a single integer, which is the perfect index of the array.

## sample

5
1 3 2 4 7

8