Best Time to Buy and Sell

Easy#arrays #greedy· solved by 0 · time limit 2.0 s

Prices of a component for $n$ days are given. Buy on one day and sell on a later day to maximise profit. Print the maximum profit (0 if you can't profit).

Input

$n$ , then $n$ prices.

Output

The maximum profit.

Constraints

$1 \le n \le 10^5$

Sample 1

Input

6
7 1 5 3 6 4

Output

Sample 2

Input

5
7 6 4 3 1

Output