import java.util.*;

public 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();
		}
		sc.close();

		int cnt = h[0];
		for (int i = 1; i < N; i++) {
			cnt += Math.max(h[i] - h[i - 1], 0);
		}

		System.out.println(cnt);
	}
} import java.util.*; util.* java public 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();
		}
		sc.close();

		int cnt = h[0];
		for (int i = 1; i < N; i++) {
			cnt += Math.max(h[i] - h[i - 1], 0);
		}

		System.out.println(cnt);
	}
} 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();
		}
		sc.close();

		int cnt = h[0];
		for (int i = 1; i < N; i++) {
			cnt += Math.max(h[i] - h[i - 1], 0);
		}

		System.out.println(cnt);
	} main {
		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();
		}
		sc.close();

		int cnt = h[0];
		for (int i = 1; i < N; i++) {
			cnt += Math.max(h[i] - h[i - 1], 0);
		}

		System.out.println(cnt);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc int[] h = new int[N]; h new int[N] N for (int i = 0; i < N; i++) {
			h[i] = sc.nextInt();
		} int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
			h[i] = sc.nextInt();
		} {
			h[i] = sc.nextInt();
		} h[i] = sc.nextInt() h[i] h i sc.nextInt() sc.nextInt sc sc.close() sc.close sc int cnt = h[0]; cnt h[0] h 0 for (int i = 1; i < N; i++) {
			cnt += Math.max(h[i] - h[i - 1], 0);
		} int i = 1; int i = 1; i 1 i < N i N i++ i++ i {
			cnt += Math.max(h[i] - h[i - 1], 0);
		} {
			cnt += Math.max(h[i] - h[i - 1], 0);
		} cnt += Math.max(h[i] - h[i - 1], 0) cnt Math.max(h[i] - h[i - 1], 0) Math.max Math h[i] - h[i - 1] h[i] h i h[i - 1] h i - 1 i 1 0 System.out.println(cnt) System.out.println System.out System System.out cnt String[] args args public 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();
		}
		sc.close();

		int cnt = h[0];
		for (int i = 1; i < N; i++) {
			cnt += Math.max(h[i] - h[i - 1], 0);
		}

		System.out.println(cnt);
	}
} public 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();
		}
		sc.close();

		int cnt = h[0];
		for (int i = 1; i < N; i++) {
			cnt += Math.max(h[i] - h[i - 1], 0);
		}

		System.out.println(cnt);
	}
} Main
import java.util.*;

public 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();
		}
		sc.close();

		int cnt = h[0];
		for (int i = 1; i < N; i++) {
			cnt += Math.max(h[i] - h[i - 1], 0);
		}

		System.out.println(cnt);
	}
}
