import java.util.*;

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 ans=0;
    for(int i=100;i>0;i--){
      boolean living=false;
      for(int j=0;j<n;j++){
        if(h[j]>=i){
          if(!living){
            living=true;
            ans++;
          }
        }else{
          living=false;
        }
      }
    }
    System.out.println(ans);
  }
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz