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.Arrays;
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 + 1];
		int[] hs = new int[N + 1];
		int[] x = new int[N + 1];
		
		for(int i = 1; i <= N; i++) {
			h[i] = sc.nextInt();
			hs[i] = h[i];
			x[i] = 0;
		}
		
		int count = 0;
		Arrays.sort(hs);
		
		for(int j = 1; j <= hs[N]; j++) {
			for(int i = 1; i <= N; i++) {
				if(x[i] < h[i]) {
					x[i] += 1;
					if(i == N || x[i + 1] == h[i + 1]) {
						count++;
					}
				}
			}
		}
		System.out.println(count);
	}
}
