#include <bits/stdc++.h>

using namespace std;

long long n,k,a,b,c,q[200005],nr,rs;
string s,x;

int main() 
{
    cin>>n;
    for (int i=1; i<=n; i++){
        cin>>q[i];
        if (q[i]<q[i-1]) rs+=abs(q[i]-q[i-1]), q[i] = q[i-1];
    }
    cout<<rs;
}
### 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 <bits/stdc++.h>

using namespace std;

long long n,k,a,b,c,q[200005],nr,rs;
string s,x;

int main() 
{
    cin>>n;
    for (int i=1; i<=n; i++){
        cin>>q[i];
        if (q[i]<q[i-1]) rs+=abs(q[i]-q[i-1]), q[i] = q[i-1];
    }
    cout<<rs;
}
```