import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve();
    }
    public void solve() {
        Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        int N = scan.nextInt();
        int answer = 0;
        int current = 0;
        for (int i = 0; i < N; i++) {
            int h = scan.nextInt();
            if (current <= h) {
                answer += (h - current);
            }
            current = h;
        }
        System.out.println(answer);
    }
} import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.Arrays; Arrays java.util import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve();
    }
    public void solve() {
        Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        int N = scan.nextInt();
        int answer = 0;
        int current = 0;
        for (int i = 0; i < N; i++) {
            int h = scan.nextInt();
            if (current <= h) {
                answer += (h - current);
            }
            current = h;
        }
        System.out.println(answer);
    }
} Main public static void main(String[] args) {
        Main main = new Main();
        main.solve();
    } main {
        Main main = new Main();
        main.solve();
    } Main main = new Main(); main new Main() main.solve() main.solve main String[] args args public void solve() {
        Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        int N = scan.nextInt();
        int answer = 0;
        int current = 0;
        for (int i = 0; i < N; i++) {
            int h = scan.nextInt();
            if (current <= h) {
                answer += (h - current);
            }
            current = h;
        }
        System.out.println(answer);
    } solve {
        Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        int N = scan.nextInt();
        int answer = 0;
        int current = 0;
        for (int i = 0; i < N; i++) {
            int h = scan.nextInt();
            if (current <= h) {
                answer += (h - current);
            }
            current = h;
        }
        System.out.println(answer);
    } Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in))); scan new Scanner(new BufferedReader(new InputStreamReader(System.in))) int N = scan.nextInt(); N scan.nextInt() scan.nextInt scan int answer = 0; answer 0 int current = 0; current 0 for (int i = 0; i < N; i++) {
            int h = scan.nextInt();
            if (current <= h) {
                answer += (h - current);
            }
            current = h;
        } int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
            int h = scan.nextInt();
            if (current <= h) {
                answer += (h - current);
            }
            current = h;
        } {
            int h = scan.nextInt();
            if (current <= h) {
                answer += (h - current);
            }
            current = h;
        } int h = scan.nextInt(); h scan.nextInt() scan.nextInt scan if (current <= h) {
                answer += (h - current);
            } current <= h current h {
                answer += (h - current);
            } answer += (h - current) answer (h - current) h current current = h current h System.out.println(answer) System.out.println System.out System System.out answer public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve();
    }
    public void solve() {
        Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        int N = scan.nextInt();
        int answer = 0;
        int current = 0;
        for (int i = 0; i < N; i++) {
            int h = scan.nextInt();
            if (current <= h) {
                answer += (h - current);
            }
            current = h;
        }
        System.out.println(answer);
    }
} public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve();
    }
    public void solve() {
        Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        int N = scan.nextInt();
        int answer = 0;
        int current = 0;
        for (int i = 0; i < N; i++) {
            int h = scan.nextInt();
            if (current <= h) {
                answer += (h - current);
            }
            current = h;
        }
        System.out.println(answer);
    }
} Main
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve();
    }
    public void solve() {
        Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        int N = scan.nextInt();
        int answer = 0;
        int current = 0;
        for (int i = 0; i < N; i++) {
            int h = scan.nextInt();
            if (current <= h) {
                answer += (h - current);
            }
            current = h;
        }
        System.out.println(answer);
    }
}
