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.awt.List;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Scanner;

public class Main {
    public static void main(String args[]) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int max = 0;
        int[] list = new int[a];
        for (int i = 0; i < a; i++) {
            list[i] = sc.nextInt();
            if(list[i] > max) {
                max = list[i];
            }
        }
        int ans = 0;
        for(int i = 0;i < max;i++){
            boolean flg = false;
            for(int j = 0; j < a; j++){
                if(list[j] > i && !flg){
                    ans++;
                    flg = true;
                } else if(list[j] <= i) {
                    flg = false;
                }
            }
        }
        System.out.println(ans);
    }
}
