Given an integer array whose length is ~n~. Find the maximum value of ~aj~ – ~ai~ for all 0 ≤ ~i~ ≤ ~j~ < ~n~.

Input

• The first line contains an integer ~n~ representing the number of elements in the array (~1~ ≤ ~n~ ≤ ~10^{5}~).

• The second line contains ~n~ integers which are elements of the array (|~ai~| ≤ ~2*10{9}~).

Output

An only integer which is the maximum difference.

Sample Input

5
2 4 1 5 3

Sample Output

4

Sample Input

6
10 5 4 3 2 1

Sample Output

0