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
import java.util.ArrayList;
import java.util.Scanner;

public class Main {
	public static void main(String args[]) {
		Scanner stdIn = new Scanner(System.in);
		int N = stdIn.nextInt();
		ArrayList<Integer> A = new ArrayList<Integer>();
		for(int i = 0; i < N; i ++) {
			A.add(stdIn.nextInt());
		}
		
		long stepSum = 0;
		
		for(int i = 1; i < N; i ++) {
			if(A.get(i - 1) <= A.get(i)) {
				continue;
			}else {
				stepSum += A.get(i - 1) - A.get(i);
				A.set(i, A.get(i - 1));
			}
		}
		
		System.out.println(stepSum);
	}
}