In a flower bed, there are N flowers, numbered 1,2,......,N. Initially, the heights of all flowers are 0. You are given a sequence h=\\{h_1,h_2,h_3,......\\} as input. You would like to change the height of Flower k to h_k for all k (1 \leq k \leq N), by repeating the following "watering" operation:

* Specify integers l and r. Increase the height of Flower x by 1 for all x such that l \leq x \leq r.



Find the minimum number of watering operations required to satisfy the condition.

Constraints

* 1 \leq N \leq 100
* 0 \leq h_i \leq 100
* All values in input are integers.

Input

Input is given from Standard Input in the following format:


N
h_1 h_2 h_3 ...... h_N


Output

Print the minimum number of watering operations required to satisfy the condition.

Examples

Input

4
1 2 2 1


Output

2


Input

5
3 1 2 3 1


Output

5


Input

8
4 23 75 0 23 96 50 100


Output

221
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] h = new int[n];
		int maxH = 0;
		for (int i = 0; i < n; i++) {
			h[i] = sc.nextInt();
			maxH = Math.max(maxH, h[i]);
		}
		
		int ans = 0;
		for (int i = 0; i < maxH; i++) {
			for (int j = 0; j < n; j++) {
				if (h[j] > 0) {
					h[j]--;
					if (j + 1 == n || h[j + 1] == 0) {
						ans++;
					}
				}
			}
		}
		
		System.out.println(ans);
	}
}
