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 count = 0;
        for(int i = 0; i < N-1; i++){
            if(h[i] > h[i+1]){
                count += h[i] - h[i+1];
            }
        }
        count += h[N-1];
        System.out.println(count);
    }
} 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 count = 0;
        for(int i = 0; i < N-1; i++){
            if(h[i] > h[i+1]){
                count += h[i] - h[i+1];
            }
        }
        count += h[N-1];
        System.out.println(count);
    }
} 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 count = 0;
        for(int i = 0; i < N-1; i++){
            if(h[i] > h[i+1]){
                count += h[i] - h[i+1];
            }
        }
        count += h[N-1];
        System.out.println(count);
    } 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 count = 0;
        for(int i = 0; i < N-1; i++){
            if(h[i] > h[i+1]){
                count += h[i] - h[i+1];
            }
        }
        count += h[N-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[] 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 count = 0; count 0 for(int i = 0; i < N-1; i++){
            if(h[i] > h[i+1]){
                count += h[i] - h[i+1];
            }
        } 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]){
                count += h[i] - h[i+1];
            }
        } {
            if(h[i] > h[i+1]){
                count += h[i] - h[i+1];
            }
        } if(h[i] > h[i+1]){
                count += h[i] - h[i+1];
            } h[i] > h[i+1] h[i] h i h[i+1] h i+1 i 1 {
                count += h[i] - h[i+1];
            } count += h[i] - h[i+1] count h[i] - h[i+1] h[i] h i h[i+1] h i+1 i 1 count += h[N-1] count h[N-1] h N-1 N 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[] h = new int[N];
        for(int i = 0; i < N; i++){
            h[i] = sc.nextInt();
        }
        sc.close();
        int count = 0;
        for(int i = 0; i < N-1; i++){
            if(h[i] > h[i+1]){
                count += h[i] - h[i+1];
            }
        }
        count += h[N-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[] h = new int[N];
        for(int i = 0; i < N; i++){
            h[i] = sc.nextInt();
        }
        sc.close();
        int count = 0;
        for(int i = 0; i < N-1; i++){
            if(h[i] > h[i+1]){
                count += h[i] - h[i+1];
            }
        }
        count += h[N-1];
        System.out.println(count);
    }
} 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 count = 0;
        for(int i = 0; i < N-1; i++){
            if(h[i] > h[i+1]){
                count += h[i] - h[i+1];
            }
        }
        count += h[N-1];
        System.out.println(count);
    }
}
