import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner reader = new Scanner(System.in);
		int N = reader.nextInt();
		int ans = 0;
		int[] h = new int[N];
		int max = 0;
		int height = 0;
		for (int i = 0; i < N; i++) {
			h[i] = reader.nextInt();
			if (h[i] > max) {
				max = h[i];
			}
		}
		while (height < max) {
			for (int i = 0; i < N; i++) {
				if (h[i] > height) {
					ans++;
					if (i < N-1 && h[i+1] > height) {
						ans--;
					}
				}
			}
			height++;
		}
		System.out.print(ans);
		reader.close();

	}

}
/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