import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        C solver = new C();
        solver.solve(1, in, out);
        out.close();
    }

    static class C {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int N = in.nextInt();
            int[] h = new int[N + 1];
            Arrays.fill(h, 0);
            for (int i = 0; i < N; i++) {
                h[i] = in.nextInt();
            }

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

    }
}
 import java.io.OutputStream; OutputStream java.io import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io import java.io.PrintWriter; PrintWriter 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) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        C solver = new C();
        solver.solve(1, in, out);
        out.close();
    }

    static class C {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int N = in.nextInt();
            int[] h = new int[N + 1];
            Arrays.fill(h, 0);
            for (int i = 0; i < N; i++) {
                h[i] = in.nextInt();
            }

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

    }
} Main public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        C solver = new C();
        solver.solve(1, in, out);
        out.close();
    } main {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        C solver = new C();
        solver.solve(1, in, out);
        out.close();
    } InputStream inputStream = System.in; inputStream System.in System System.in OutputStream outputStream = System.out; outputStream System.out System System.out Scanner in = new Scanner(inputStream); in new Scanner(inputStream) PrintWriter out = new PrintWriter(outputStream); out new PrintWriter(outputStream) C solver = new C(); solver new C() solver.solve(1, in, out) solver.solve solver 1 in out out.close() out.close out String[] args args static class C {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int N = in.nextInt();
            int[] h = new int[N + 1];
            Arrays.fill(h, 0);
            for (int i = 0; i < N; i++) {
                h[i] = in.nextInt();
            }

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

    } C public void solve(int testNumber, Scanner in, PrintWriter out) {
            int N = in.nextInt();
            int[] h = new int[N + 1];
            Arrays.fill(h, 0);
            for (int i = 0; i < N; i++) {
                h[i] = in.nextInt();
            }

            int count = 0;
            for (int i = 0; i < N; i++) {
                if (h[i] > h[i + 1]) {
                    count += h[i] - h[i + 1];
                }
            }
            out.println(count);
        } solve {
            int N = in.nextInt();
            int[] h = new int[N + 1];
            Arrays.fill(h, 0);
            for (int i = 0; i < N; i++) {
                h[i] = in.nextInt();
            }

            int count = 0;
            for (int i = 0; i < N; i++) {
                if (h[i] > h[i + 1]) {
                    count += h[i] - h[i + 1];
                }
            }
            out.println(count);
        } int N = in.nextInt(); N in.nextInt() in.nextInt in int[] h = new int[N + 1]; h new int[N + 1] N + 1 N 1 Arrays.fill(h, 0) Arrays.fill Arrays h 0 for (int i = 0; i < N; i++) {
                h[i] = in.nextInt();
            } int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
                h[i] = in.nextInt();
            } {
                h[i] = in.nextInt();
            } h[i] = in.nextInt() h[i] h i in.nextInt() in.nextInt in int count = 0; count 0 for (int i = 0; i < N; i++) {
                if (h[i] > h[i + 1]) {
                    count += h[i] - h[i + 1];
                }
            } int i = 0; int i = 0; i 0 i < N i N 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 out.println(count) out.println out count int testNumber testNumber Scanner in in PrintWriter out out public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        C solver = new C();
        solver.solve(1, in, out);
        out.close();
    }

    static class C {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int N = in.nextInt();
            int[] h = new int[N + 1];
            Arrays.fill(h, 0);
            for (int i = 0; i < N; i++) {
                h[i] = in.nextInt();
            }

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

    }
} public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        C solver = new C();
        solver.solve(1, in, out);
        out.close();
    }

    static class C {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int N = in.nextInt();
            int[] h = new int[N + 1];
            Arrays.fill(h, 0);
            for (int i = 0; i < N; i++) {
                h[i] = in.nextInt();
            }

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

    }
} Main
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        C solver = new C();
        solver.solve(1, in, out);
        out.close();
    }

    static class C {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int N = in.nextInt();
            int[] h = new int[N + 1];
            Arrays.fill(h, 0);
            for (int i = 0; i < N; i++) {
                h[i] = in.nextInt();
            }

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

    }
}

