#include <bits/stdc++.h>
using namespace std;
template <class T1>
void deb(T1 e) {
  cout << e << endl;
}
template <class T1, class T2>
void deb(T1 e1, T2 e2) {
  cout << e1 << " " << e2 << endl;
}
template <class T1, class T2, class T3>
void deb(T1 e1, T2 e2, T3 e3) {
  cout << e1 << " " << e2 << " " << e3 << endl;
}
template <class T1, class T2, class T3, class T4>
void deb(T1 e1, T2 e2, T3 e3, T4 e4) {
  cout << e1 << " " << e2 << " " << e3 << " " << e4 << endl;
}
template <class T1, class T2, class T3, class T4, class T5>
void deb(T1 e1, T2 e2, T3 e3, T4 e4, T5 e5) {
  cout << e1 << " " << e2 << " " << e3 << " " << e4 << " " << e5 << endl;
}
template <class T1, class T2, class T3, class T4, class T5, class T6>
void deb(T1 e1, T2 e2, T3 e3, T4 e4, T5 e5, T6 e6) {
  cout << e1 << " " << e2 << " " << e3 << " " << e4 << " " << e5 << " " << e6
       << endl;
}
long long sqr(long long n) { return n * n; }
double LOG(long long a, long long b) { return (log(a) / log(b)); }
long long GCD(long long a, long long b) {
  if (a < 0) return GCD(-a, b);
  if (b < 0) return GCD(a, -b);
  return (!b) ? a : GCD(b, a % b);
}
long long LCM(long long a, long long b) {
  if (a < 0) return LCM(-a, b);
  if (b < 0) return LCM(a, -b);
  return (a * (b / GCD(a, b)));
}
long long BigMod(long long B, long long P, long long M) {
  if (!P) return 1;
  if (!(P % 2)) return sqr(BigMod(B, P / 2, M)) % M;
  return (B % M) * (BigMod(B, P - 1, M)) % M;
}
vector<long long> nums;
int main(void) {
  long long n, i, x;
  cin >> n;
  nums.clear();
  for (i = 0; i < n; i++) {
    scanf("%I64d", &x);
    nums.push_back(x);
  }
  long long res = 0ll;
  long long prevMove = 0ll;
  for (i = 1; i < n; i++) {
    if (nums[i] < nums[i - 1]) {
      res += nums[i - 1] - nums[i];
    }
  }
  deb(res);
  return 0;
}

### Prompt

Construct a Cpp code solution to the problem outlined:

The Little Elephant loves sortings.

He has an array a consisting of n integers. Let's number the array elements from 1 to n, then the i-th element will be denoted as ai. The Little Elephant can make one move to choose an arbitrary pair of integers l and r (1 ≤ l ≤ r ≤ n) and increase ai by 1 for all i such that l ≤ i ≤ r.

Help the Little Elephant find the minimum number of moves he needs to convert array a to an arbitrary array sorted in the non-decreasing order. Array a, consisting of n elements, is sorted in the non-decreasing order if for any i (1 ≤ i < n) ai ≤ ai + 1 holds.

Input

The first line contains a single integer n (1 ≤ n ≤ 105) — the size of array a. The next line contains n integers, separated by single spaces — array a (1 ≤ ai ≤ 109). The array elements are listed in the line in the order of their index's increasing.

Output

In a single line print a single integer — the answer to the problem.

Please, do not use the %lld specifier to read or write 64-bit integers in С++. It is preferred to use the cin, cout streams or the %I64d specifier.

Examples

Input

3
1 2 3


Output

0


Input

3
3 2 1


Output

2


Input

4
7 4 1 47


Output

6

Note

In the first sample the array is already sorted in the non-decreasing order, so the answer is 0.

In the second sample you need to perform two operations: first increase numbers from second to third (after that the array will be: [3, 3, 2]), and second increase only the last element (the array will be: [3, 3, 3]).

In the third sample you should make at least 6 steps. The possible sequence of the operations is: (2; 3), (2; 3), (2; 3), (3; 3), (3; 3), (3; 3). After that the array converts to [7, 7, 7, 47].

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
template <class T1>
void deb(T1 e) {
  cout << e << endl;
}
template <class T1, class T2>
void deb(T1 e1, T2 e2) {
  cout << e1 << " " << e2 << endl;
}
template <class T1, class T2, class T3>
void deb(T1 e1, T2 e2, T3 e3) {
  cout << e1 << " " << e2 << " " << e3 << endl;
}
template <class T1, class T2, class T3, class T4>
void deb(T1 e1, T2 e2, T3 e3, T4 e4) {
  cout << e1 << " " << e2 << " " << e3 << " " << e4 << endl;
}
template <class T1, class T2, class T3, class T4, class T5>
void deb(T1 e1, T2 e2, T3 e3, T4 e4, T5 e5) {
  cout << e1 << " " << e2 << " " << e3 << " " << e4 << " " << e5 << endl;
}
template <class T1, class T2, class T3, class T4, class T5, class T6>
void deb(T1 e1, T2 e2, T3 e3, T4 e4, T5 e5, T6 e6) {
  cout << e1 << " " << e2 << " " << e3 << " " << e4 << " " << e5 << " " << e6
       << endl;
}
long long sqr(long long n) { return n * n; }
double LOG(long long a, long long b) { return (log(a) / log(b)); }
long long GCD(long long a, long long b) {
  if (a < 0) return GCD(-a, b);
  if (b < 0) return GCD(a, -b);
  return (!b) ? a : GCD(b, a % b);
}
long long LCM(long long a, long long b) {
  if (a < 0) return LCM(-a, b);
  if (b < 0) return LCM(a, -b);
  return (a * (b / GCD(a, b)));
}
long long BigMod(long long B, long long P, long long M) {
  if (!P) return 1;
  if (!(P % 2)) return sqr(BigMod(B, P / 2, M)) % M;
  return (B % M) * (BigMod(B, P - 1, M)) % M;
}
vector<long long> nums;
int main(void) {
  long long n, i, x;
  cin >> n;
  nums.clear();
  for (i = 0; i < n; i++) {
    scanf("%I64d", &x);
    nums.push_back(x);
  }
  long long res = 0ll;
  long long prevMove = 0ll;
  for (i = 1; i < n; i++) {
    if (nums[i] < nums[i - 1]) {
      res += nums[i - 1] - nums[i];
    }
  }
  deb(res);
  return 0;
}

```