import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		int[] nums = new int[n];
		
		int count = 0;
		
		for(int i=0; i<n; i++) {
			nums[i] = sc.nextInt();
			
			if(i==0) {
				count = nums[0];
			}else {
				count += Math.max(0, nums[i]-nums[i-1]);
			}
		}
		System.out.println(count);
	}
} import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		int[] nums = new int[n];
		
		int count = 0;
		
		for(int i=0; i<n; i++) {
			nums[i] = sc.nextInt();
			
			if(i==0) {
				count = nums[0];
			}else {
				count += Math.max(0, nums[i]-nums[i-1]);
			}
		}
		System.out.println(count);
	}
} Main public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		int[] nums = new int[n];
		
		int count = 0;
		
		for(int i=0; i<n; i++) {
			nums[i] = sc.nextInt();
			
			if(i==0) {
				count = nums[0];
			}else {
				count += Math.max(0, nums[i]-nums[i-1]);
			}
		}
		System.out.println(count);
	} main {

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		int[] nums = new int[n];
		
		int count = 0;
		
		for(int i=0; i<n; i++) {
			nums[i] = sc.nextInt();
			
			if(i==0) {
				count = nums[0];
			}else {
				count += Math.max(0, nums[i]-nums[i-1]);
			}
		}
		System.out.println(count);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc int[] nums = new int[n]; nums new int[n] n int count = 0; count 0 for(int i=0; i<n; i++) {
			nums[i] = sc.nextInt();
			
			if(i==0) {
				count = nums[0];
			}else {
				count += Math.max(0, nums[i]-nums[i-1]);
			}
		} int i=0; int i=0; i 0 i<n i n i++ i++ i {
			nums[i] = sc.nextInt();
			
			if(i==0) {
				count = nums[0];
			}else {
				count += Math.max(0, nums[i]-nums[i-1]);
			}
		} {
			nums[i] = sc.nextInt();
			
			if(i==0) {
				count = nums[0];
			}else {
				count += Math.max(0, nums[i]-nums[i-1]);
			}
		} nums[i] = sc.nextInt() nums[i] nums i sc.nextInt() sc.nextInt sc if(i==0) {
				count = nums[0];
			}else {
				count += Math.max(0, nums[i]-nums[i-1]);
			} i==0 i 0 {
				count = nums[0];
			} count = nums[0] count nums[0] nums 0 {
				count += Math.max(0, nums[i]-nums[i-1]);
			} count += Math.max(0, nums[i]-nums[i-1]) count Math.max(0, nums[i]-nums[i-1]) Math.max Math 0 nums[i]-nums[i-1] nums[i] nums i nums[i-1] nums i-1 i 1 System.out.println(count) System.out.println System.out System System.out count String[] args args public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		int[] nums = new int[n];
		
		int count = 0;
		
		for(int i=0; i<n; i++) {
			nums[i] = sc.nextInt();
			
			if(i==0) {
				count = nums[0];
			}else {
				count += Math.max(0, nums[i]-nums[i-1]);
			}
		}
		System.out.println(count);
	}
} public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		int[] nums = new int[n];
		
		int count = 0;
		
		for(int i=0; i<n; i++) {
			nums[i] = sc.nextInt();
			
			if(i==0) {
				count = nums[0];
			}else {
				count += Math.max(0, nums[i]-nums[i-1]);
			}
		}
		System.out.println(count);
	}
} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		int[] nums = new int[n];
		
		int count = 0;
		
		for(int i=0; i<n; i++) {
			nums[i] = sc.nextInt();
			
			if(i==0) {
				count = nums[0];
			}else {
				count += Math.max(0, nums[i]-nums[i-1]);
			}
		}
		System.out.println(count);
	}
}
