
import java.util.Scanner;

class Main {

	public static void main(String[] args) {
		new Main().exec();
	}

	void exec() {
		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 act = 0;
		int result = 0;

		for (int i = 0; i < n; i++) {
			if (act > h[i]) {
				act = h[i];
			}else {
				result += h[i] - act;
				act = h[i];
			}
		}

		System.out.println(result);
		sc.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