import java.util.*;
class Main{
    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int[] h = new int[n+1];
        int max = 0;
        for(int i = 0; i < n; i++){
            h[i] = scanner.nextInt();
            max = Math.max(max, h[i]);
        }
        int count = 0;
        for(int i = 1; i <= max; i++){
            for(int j = 0; j < n; j++){
                if(h[j] >= i && h[j+1] < i){
                    count++;
                }
            }
        }
        System.out.println(count);
    }
}
/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