import java.util.*;
public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int N  = sc.nextInt();
        ArrayList<Integer> List = new ArrayList<>();
        int sum=0,h_num=0;
        for(int a=0;a<N;a++) {
            List.add(sc.nextInt());
            sum+=List.get(a);
        }
        h_num+=List.get(0);
        for(int a=1;a<N;a++){
            int num2=0;
            if(List.get(a-1)<List.get(a))num2 = List.get(a) - List.get(a-1);
            h_num+=num2;
        }
        System.out.println(h_num);
    }
}
/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