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 N = sc.nextInt();
   int[] h =new int[N];
   for(int i=0;i<N;i++) h[i] = sc.nextInt();
   
   int tmpmin=h[0];
   int tmpmax;
   boolean up= true;
   int ans =h[0];
   for(int i=1;i<N;i++)
   {
     if(up)
     {
       if(h[i-1]>h[i]) 
       {
         up=false;
         tmpmax=h[i-1];
         ans+=tmpmax-tmpmin;
       }
     }
     else
     {
       if(h[i-1]<h[i])
       {
         up=true;
         tmpmin=h[i-1];
       }
     }
   }
   if(up) ans+= h[N-1]-tmpmin;
   
   System.out.println(ans);
 }
}