import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int h[] = new int[n+1];
		for (int i = 1; i <= n; i++) {
			h[i] = sc.nextInt();
		}
h[0]=0;
int ans=0;
for (int i =0; i <= n-1; i++) {
if(h[i]<h[i+1]){
ans+=h[i+1]-h[i];
}
}
System.out.println(ans);
	}
} 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 h[] = new int[n+1];
		for (int i = 1; i <= n; i++) {
			h[i] = sc.nextInt();
		}
h[0]=0;
int ans=0;
for (int i =0; i <= n-1; i++) {
if(h[i]<h[i+1]){
ans+=h[i+1]-h[i];
}
}
System.out.println(ans);
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int h[] = new int[n+1];
		for (int i = 1; i <= n; i++) {
			h[i] = sc.nextInt();
		}
h[0]=0;
int ans=0;
for (int i =0; i <= n-1; i++) {
if(h[i]<h[i+1]){
ans+=h[i+1]-h[i];
}
}
System.out.println(ans);
	} main {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int h[] = new int[n+1];
		for (int i = 1; i <= n; i++) {
			h[i] = sc.nextInt();
		}
h[0]=0;
int ans=0;
for (int i =0; i <= n-1; i++) {
if(h[i]<h[i+1]){
ans+=h[i+1]-h[i];
}
}
System.out.println(ans);
	} 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+1]; h new int[n+1] n+1 n 1 for (int i = 1; i <= n; i++) {
			h[i] = sc.nextInt();
		} int i = 1; int i = 1; i 1 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 h[0]=0 h[0] h 0 0 int ans=0; ans 0 for (int i =0; i <= n-1; i++) {
if(h[i]<h[i+1]){
ans+=h[i+1]-h[i];
}
} int i =0; int i =0; i 0 i <= n-1 i n-1 n 1 i++ i++ i {
if(h[i]<h[i+1]){
ans+=h[i+1]-h[i];
}
} {
if(h[i]<h[i+1]){
ans+=h[i+1]-h[i];
}
} if(h[i]<h[i+1]){
ans+=h[i+1]-h[i];
} h[i]<h[i+1] h[i] h i h[i+1] h i+1 i 1 {
ans+=h[i+1]-h[i];
} ans+=h[i+1]-h[i] ans h[i+1]-h[i] h[i+1] h i+1 i 1 h[i] h i System.out.println(ans) System.out.println System.out System System.out ans 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+1];
		for (int i = 1; i <= n; i++) {
			h[i] = sc.nextInt();
		}
h[0]=0;
int ans=0;
for (int i =0; i <= n-1; i++) {
if(h[i]<h[i+1]){
ans+=h[i+1]-h[i];
}
}
System.out.println(ans);
	}
} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int h[] = new int[n+1];
		for (int i = 1; i <= n; i++) {
			h[i] = sc.nextInt();
		}
h[0]=0;
int ans=0;
for (int i =0; i <= n-1; i++) {
if(h[i]<h[i+1]){
ans+=h[i+1]-h[i];
}
}
System.out.println(ans);
	}
} 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 h[] = new int[n+1];
		for (int i = 1; i <= n; i++) {
			h[i] = sc.nextInt();
		}
h[0]=0;
int ans=0;
for (int i =0; i <= n-1; i++) {
if(h[i]<h[i+1]){
ans+=h[i+1]-h[i];
}
}
System.out.println(ans);
	}
}