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 = scan.nextInt();
    int[] a = new int[n];
    for (int i=0;i<n;i++){
      a[i] = scan.nextInt();
    }

    long sum = 0;
    while (true){
      boolean flag = true;
      for (int i=0;i<n;i++){
        if (a[i] == 0){
          if (flag == false){
            break;
          }
        }
        else{
          a[i] -= 1;
          flag = false;
        }
      }

      if (flag == true){
        System.out.println(sum);
        return;
      }

      sum += 1;


    }
  }
}
