#include<iostream>

using namespace std;

const int N=2e5+10;

int a[N];
long long res=0;

int main()
{
	int x,y,n;
	cin>>n>>x;
	for(int i=1;i<n;i++)
	{
		scanf("%d",&y);
		if(y<x) res+=x-y;
		else x=y;
	}
	cout<< res <<endl;
	return 0; 
}
### Prompt

Please create a solution in CPP to the following problem:

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<iostream>

using namespace std;

const int N=2e5+10;

int a[N];
long long res=0;

int main()
{
	int x,y,n;
	cin>>n>>x;
	for(int i=1;i<n;i++)
	{
		scanf("%d",&y);
		if(y<x) res+=x-y;
		else x=y;
	}
	cout<< res <<endl;
	return 0; 
}
```