MAXDIFF

You are given a sequence of ~N~ natural numbers: ~a_1~, ~a_2~, ~...~, ~a_N~. The maximum value of the difference ~a_i - a_j~ is requested, where ~a_i~ and ~a_j~ are two terms of the sequence and ~i < j~.

Input

The program reads data from the text file "maxdiff.in". The first line contains an integer ~N~, which is the number of terms in the sequence. The second line contains the ~N~ natural numbers ~a_1~, ~a_2~, ~...~, ~a_N~ separated in pairs by spaces.

Ouput

The result must be printed to the text file "maxdiff.out". Only one line should be printed containing a natural number: the maximum value of the difference ~a_i - a_j~, where ~a_i~ and ~a_j~ are terms of the sequence and ~i < j~.

Constraints

~1 \le N \le 1.000.000~

Time limit: ~1~ sec.
Maximum Available Memory: ~1~ MB.

Example of Input - Output

STDIN (maxdiff.in)

10
3 12 3 0 28 9 13 4 23 7

STDOUT (maxdiff.out)

24