import java.util.Scanner;

import java.util.Arrays;
import java.util.ArrayList;

public class Main {
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int [] h = new int[N];
		int hmin = 1000;
		for (int i = 0; i < N; i++) {
			h[i] = sc.nextInt();
		}
		int total = h[0];
		if (N == 1) {
			System.out.println(total);
		}
		else if (N==2) {
			total = Math.max(h[0], h[1]);
			System.out.println(total);
		}
		else {
			for (int i = 1; i < N; i++) {
				if(h[i] > h[i-1]) {
					total += h[i] - h[i-1];
				}
			}
			System.out.println(total);
		}
	}
}	 import java.util.Scanner; Scanner java.util import java.util.Arrays; Arrays java.util import java.util.ArrayList; ArrayList 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];
		int hmin = 1000;
		for (int i = 0; i < N; i++) {
			h[i] = sc.nextInt();
		}
		int total = h[0];
		if (N == 1) {
			System.out.println(total);
		}
		else if (N==2) {
			total = Math.max(h[0], h[1]);
			System.out.println(total);
		}
		else {
			for (int i = 1; i < N; i++) {
				if(h[i] > h[i-1]) {
					total += h[i] - h[i-1];
				}
			}
			System.out.println(total);
		}
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int [] h = new int[N];
		int hmin = 1000;
		for (int i = 0; i < N; i++) {
			h[i] = sc.nextInt();
		}
		int total = h[0];
		if (N == 1) {
			System.out.println(total);
		}
		else if (N==2) {
			total = Math.max(h[0], h[1]);
			System.out.println(total);
		}
		else {
			for (int i = 1; i < N; i++) {
				if(h[i] > h[i-1]) {
					total += h[i] - h[i-1];
				}
			}
			System.out.println(total);
		}
	} main {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int [] h = new int[N];
		int hmin = 1000;
		for (int i = 0; i < N; i++) {
			h[i] = sc.nextInt();
		}
		int total = h[0];
		if (N == 1) {
			System.out.println(total);
		}
		else if (N==2) {
			total = Math.max(h[0], h[1]);
			System.out.println(total);
		}
		else {
			for (int i = 1; i < N; i++) {
				if(h[i] > h[i-1]) {
					total += h[i] - h[i-1];
				}
			}
			System.out.println(total);
		}
	} 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 int hmin = 1000; hmin 1000 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 int total = h[0]; total h[0] h 0 if (N == 1) {
			System.out.println(total);
		}
		else if (N==2) {
			total = Math.max(h[0], h[1]);
			System.out.println(total);
		}
		else {
			for (int i = 1; i < N; i++) {
				if(h[i] > h[i-1]) {
					total += h[i] - h[i-1];
				}
			}
			System.out.println(total);
		} N == 1 N 1 {
			System.out.println(total);
		} System.out.println(total) System.out.println System.out System System.out total if (N==2) {
			total = Math.max(h[0], h[1]);
			System.out.println(total);
		}
		else {
			for (int i = 1; i < N; i++) {
				if(h[i] > h[i-1]) {
					total += h[i] - h[i-1];
				}
			}
			System.out.println(total);
		} N==2 N 2 {
			total = Math.max(h[0], h[1]);
			System.out.println(total);
		} total = Math.max(h[0], h[1]) total Math.max(h[0], h[1]) Math.max Math h[0] h 0 h[1] h 1 System.out.println(total) System.out.println System.out System System.out total {
			for (int i = 1; i < N; i++) {
				if(h[i] > h[i-1]) {
					total += h[i] - h[i-1];
				}
			}
			System.out.println(total);
		} for (int i = 1; i < N; i++) {
				if(h[i] > h[i-1]) {
					total += h[i] - h[i-1];
				}
			} int i = 1; int i = 1; i 1 i < N i N i++ i++ i {
				if(h[i] > h[i-1]) {
					total += h[i] - h[i-1];
				}
			} {
				if(h[i] > h[i-1]) {
					total += h[i] - h[i-1];
				}
			} if(h[i] > h[i-1]) {
					total += h[i] - h[i-1];
				} h[i] > h[i-1] h[i] h i h[i-1] h i-1 i 1 {
					total += h[i] - h[i-1];
				} total += h[i] - h[i-1] total h[i] - h[i-1] h[i] h i h[i-1] h i-1 i 1 System.out.println(total) System.out.println System.out System System.out total 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];
		int hmin = 1000;
		for (int i = 0; i < N; i++) {
			h[i] = sc.nextInt();
		}
		int total = h[0];
		if (N == 1) {
			System.out.println(total);
		}
		else if (N==2) {
			total = Math.max(h[0], h[1]);
			System.out.println(total);
		}
		else {
			for (int i = 1; i < N; i++) {
				if(h[i] > h[i-1]) {
					total += h[i] - h[i-1];
				}
			}
			System.out.println(total);
		}
	}
} public class Main {
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int [] h = new int[N];
		int hmin = 1000;
		for (int i = 0; i < N; i++) {
			h[i] = sc.nextInt();
		}
		int total = h[0];
		if (N == 1) {
			System.out.println(total);
		}
		else if (N==2) {
			total = Math.max(h[0], h[1]);
			System.out.println(total);
		}
		else {
			for (int i = 1; i < N; i++) {
				if(h[i] > h[i-1]) {
					total += h[i] - h[i-1];
				}
			}
			System.out.println(total);
		}
	}
} Main
import java.util.Scanner;

import java.util.Arrays;
import java.util.ArrayList;

public class Main {
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int [] h = new int[N];
		int hmin = 1000;
		for (int i = 0; i < N; i++) {
			h[i] = sc.nextInt();
		}
		int total = h[0];
		if (N == 1) {
			System.out.println(total);
		}
		else if (N==2) {
			total = Math.max(h[0], h[1]);
			System.out.println(total);
		}
		else {
			for (int i = 1; i < N; i++) {
				if(h[i] > h[i-1]) {
					total += h[i] - h[i-1];
				}
			}
			System.out.println(total);
		}
	}
}	
