import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        int[] h = new int[N];

        h[0] = sc.nextInt();
        int ans = h[0];
        for(int i = 1; i < N; i++){
            h[i] = sc.nextInt();
            if(h[i-1] >= h[i]) continue;
            ans += h[i] - h[i-1];
        }
        
        System.out.println(ans);
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) throws Exception {
        
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        int[] h = new int[N];

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

        int N = sc.nextInt();
        int[] h = new int[N];

        h[0] = sc.nextInt();
        int ans = h[0];
        for(int i = 1; i < N; i++){
            h[i] = sc.nextInt();
            if(h[i-1] >= h[i]) continue;
            ans += h[i] - h[i-1];
        }
        
        System.out.println(ans);
    } main {
        
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        int[] h = new int[N];

        h[0] = sc.nextInt();
        int ans = h[0];
        for(int i = 1; i < N; i++){
            h[i] = sc.nextInt();
            if(h[i-1] >= h[i]) continue;
            ans += h[i] - h[i-1];
        }
        
        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]; h new int[N] N h[0] = sc.nextInt() h[0] h 0 sc.nextInt() sc.nextInt sc int ans = h[0]; ans h[0] h 0 for(int i = 1; i < N; i++){
            h[i] = sc.nextInt();
            if(h[i-1] >= h[i]) continue;
            ans += h[i] - h[i-1];
        } int i = 1; int i = 1; i 1 i < N i N i++ i++ i {
            h[i] = sc.nextInt();
            if(h[i-1] >= h[i]) continue;
            ans += h[i] - h[i-1];
        } {
            h[i] = sc.nextInt();
            if(h[i-1] >= h[i]) continue;
            ans += h[i] - h[i-1];
        } h[i] = sc.nextInt() h[i] h i sc.nextInt() sc.nextInt sc if(h[i-1] >= h[i]) continue; h[i-1] >= h[i] h[i-1] h i-1 i 1 h[i] h i continue; ans += h[i] - h[i-1] ans h[i] - h[i-1] h[i] h i h[i-1] h i-1 i 1 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) throws Exception {
        
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        int[] h = new int[N];

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

        int N = sc.nextInt();
        int[] h = new int[N];

        h[0] = sc.nextInt();
        int ans = h[0];
        for(int i = 1; i < N; i++){
            h[i] = sc.nextInt();
            if(h[i-1] >= h[i]) continue;
            ans += h[i] - h[i-1];
        }
        
        System.out.println(ans);
    }
} Main
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        int[] h = new int[N];

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