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 sc = new Scanner(System.in);
    int K = sc.nextInt();
    int h[] = new int[K+1];
    int landCt =0;
    int answer=0;
    h[0]=0;
    for(int i=1;i<=K;i++){
      h[i] = sc.nextInt();
    }
    for(int i=0;i<101;i++){
      landCt=0;
      for(int j=0;j<K;j++){
        if(h[j]==0&&h[j+1]>0){
          landCt=landCt+1;
        }
      }
      answer = answer + landCt;
      oneMinus(h);
    }
      System.out.println(answer);   
  }
  
  public static void oneMinus(int[] h){
    for(int i=0;i<h.length;i++){
      if(h[i]!=0){
        h[i]=h[i]-1;
      }
    }
  }
  
}