<? echo $row['title']." - ".$MSG_PROBLEM."

Time Limit: 2 sec / Memory Limit: 1024 MB

Score :

300

points

Problem Statement

N

persons are standing in a row. The height of the

i

-th person from the front is

A_i

.
We want to have each person stand on a stool of some heights - at least zero - so that the following condition is satisfied for every person:
Condition: Nobody in front of the person is taller than the person. Here, the height of a person includes the stool.
Find the minimum total height of the stools needed to meet this goal.

Constraints

$\leq N \leq 2\times 10^5$
$\leq A_i \leq 10^9$
All values in input are integers.

Input

Input is given from Standard Input in the following format:

 $N$  $A_1$  $\ldots$  $A_N$

Output

Print the minimum total height of the stools needed to meet the goal.

2364: Step

Description

Problem Statement

Constraints

Input

Output

Sample Input Copy

Sample Output Copy

HINT

Source/Category