import java.util.ArrayList;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        ArrayList<Integer> list = new ArrayList<>();

        for (int i = 0; i < N; i++) {
            list.add(sc.nextInt());
        }

        sc.close();

        int ans = 0;
        int active = 0;

        for (int i = 0; i < N; i++) {
            int tmp = list.get(i);
            if (active < tmp) {
                ans += tmp - active;
            }
            active = tmp;
        }

        System.out.println(ans);
    }
} import java.util.ArrayList; ArrayList java.util 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();
        ArrayList<Integer> list = new ArrayList<>();

        for (int i = 0; i < N; i++) {
            list.add(sc.nextInt());
        }

        sc.close();

        int ans = 0;
        int active = 0;

        for (int i = 0; i < N; i++) {
            int tmp = list.get(i);
            if (active < tmp) {
                ans += tmp - active;
            }
            active = tmp;
        }

        System.out.println(ans);
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        ArrayList<Integer> list = new ArrayList<>();

        for (int i = 0; i < N; i++) {
            list.add(sc.nextInt());
        }

        sc.close();

        int ans = 0;
        int active = 0;

        for (int i = 0; i < N; i++) {
            int tmp = list.get(i);
            if (active < tmp) {
                ans += tmp - active;
            }
            active = tmp;
        }

        System.out.println(ans);
    } main {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        ArrayList<Integer> list = new ArrayList<>();

        for (int i = 0; i < N; i++) {
            list.add(sc.nextInt());
        }

        sc.close();

        int ans = 0;
        int active = 0;

        for (int i = 0; i < N; i++) {
            int tmp = list.get(i);
            if (active < tmp) {
                ans += tmp - active;
            }
            active = tmp;
        }

        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 ArrayList<Integer> list = new ArrayList<>(); list new ArrayList<>() for (int i = 0; i < N; i++) {
            list.add(sc.nextInt());
        } int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
            list.add(sc.nextInt());
        } {
            list.add(sc.nextInt());
        } list.add(sc.nextInt()) list.add list sc.nextInt() sc.nextInt sc sc.close() sc.close sc int ans = 0; ans 0 int active = 0; active 0 for (int i = 0; i < N; i++) {
            int tmp = list.get(i);
            if (active < tmp) {
                ans += tmp - active;
            }
            active = tmp;
        } int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
            int tmp = list.get(i);
            if (active < tmp) {
                ans += tmp - active;
            }
            active = tmp;
        } {
            int tmp = list.get(i);
            if (active < tmp) {
                ans += tmp - active;
            }
            active = tmp;
        } int tmp = list.get(i); tmp list.get(i) list.get list i if (active < tmp) {
                ans += tmp - active;
            } active < tmp active tmp {
                ans += tmp - active;
            } ans += tmp - active ans tmp - active tmp active active = tmp active tmp 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();
        ArrayList<Integer> list = new ArrayList<>();

        for (int i = 0; i < N; i++) {
            list.add(sc.nextInt());
        }

        sc.close();

        int ans = 0;
        int active = 0;

        for (int i = 0; i < N; i++) {
            int tmp = list.get(i);
            if (active < tmp) {
                ans += tmp - active;
            }
            active = tmp;
        }

        System.out.println(ans);
    }
} public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        ArrayList<Integer> list = new ArrayList<>();

        for (int i = 0; i < N; i++) {
            list.add(sc.nextInt());
        }

        sc.close();

        int ans = 0;
        int active = 0;

        for (int i = 0; i < N; i++) {
            int tmp = list.get(i);
            if (active < tmp) {
                ans += tmp - active;
            }
            active = tmp;
        }

        System.out.println(ans);
    }
} Main
import java.util.ArrayList;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        ArrayList<Integer> list = new ArrayList<>();

        for (int i = 0; i < N; i++) {
            list.add(sc.nextInt());
        }

        sc.close();

        int ans = 0;
        int active = 0;

        for (int i = 0; i < N; i++) {
            int tmp = list.get(i);
            if (active < tmp) {
                ans += tmp - active;
            }
            active = tmp;
        }

        System.out.println(ans);
    }
}