#include<bits/stdc++.h>
using namespace std;
int main(){
	int n;
	scanf("%d",&n);
	long long ans=0;
	long long maxx=0;
	for(int i=1;i<=n;i++){
		long long x;
		scanf("%lld",&x);
		maxx=max(maxx,x);
		ans+=maxx-x;
	}
	printf("%lld",ans);
	return 0;
}
### Prompt

Construct a Cpp code solution to the problem outlined:

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

* 1 \leq N \leq 2\times 10^5
* 1 \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.

Examples

Input

5
2 1 5 4 3


Output

4


Input

5
3 3 3 3 3


Output

0

### Response

```cpp
#include<bits/stdc++.h>
using namespace std;
int main(){
	int n;
	scanf("%d",&n);
	long long ans=0;
	long long maxx=0;
	for(int i=1;i<=n;i++){
		long long x;
		scanf("%lld",&x);
		maxx=max(maxx,x);
		ans+=maxx-x;
	}
	printf("%lld",ans);
	return 0;
}
```