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.*;

public class Main {
	public static void main(String[] args)  {
		Scanner scan = new Scanner(System.in);
		int n =Integer.parseInt(scan.next());
		int[] h=new int [n];
		int max=0;
		for (int i=0;i<n;++i) {
			h[i]=Integer.parseInt(scan.next());
			max=Math.max(max, h[i]);
		}
		
		int count=0;
		boolean last=false;
		while (max>0) {
			--max;
			count++;
			last=false;
			for (int i=0;i<n;++i) {
				if (h[i]>0) {	
					last=true;
					--h[i];
				}else if (i+1<n&&h[i+1]>0&&last) {
					++count;
				}
			}
			
			
		}
		
		System.out.print(count);

	}
}
//end
