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.*;

class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int N;
    N = sc.nextInt();
    int h[] = new int[N];
    boolean exi = false;
    int ans = 0;
    for(int i=0; i<N; i++) h[i] = sc.nextInt();
    for(int i=1; i<=100; i++){
      for(int j=0; j<N; j++){
        if(h[j] >= i){
          if(exi == false){
            ans++;
            exi = true;
          }
        }else{
          exi = false;
        }
      }
      exi = false;
    }
    System.out.println(ans);
                               
  }
}