Caisa solved the problem with the sugar and now he is on the way back to home. 

Caisa is playing a mobile game during his path. There are (n + 1) pylons numbered from 0 to n in this game. The pylon with number 0 has zero height, the pylon with number i (i > 0) has height hi. The goal of the game is to reach n-th pylon, and the only move the player can do is to jump from the current pylon (let's denote its number as k) to the next one (its number will be k + 1). When the player have made such a move, its energy increases by hk - hk + 1 (if this value is negative the player loses energy). The player must have non-negative amount of energy at any moment of the time. 

Initially Caisa stand at 0 pylon and has 0 energy. The game provides a special opportunity: one can pay a single dollar and increase the height of anyone pylon by one. Caisa may use that opportunity several times, but he doesn't want to spend too much money. What is the minimal amount of money he must paid to reach the goal of the game?

Input

The first line contains integer n (1 ≤ n ≤ 105). The next line contains n integers h1, h2, ..., hn (1 ≤ hi ≤ 105) representing the heights of the pylons.

Output

Print a single number representing the minimum number of dollars paid by Caisa.

Examples

Input

5
3 4 3 2 4


Output

4


Input

3
4 4 4


Output

4

Note

In the first sample he can pay 4 dollars and increase the height of pylon with number 0 by 4 units. Then he can safely pass to the last pylon.
import java.io.*;
import java.lang.management.GarbageCollectorMXBean;
import java.lang.management.ManagementFactory;
import java.util.Arrays;
import java.util.Random;
import java.util.Scanner;
import java.util.StringTokenizer;

import static java.lang.Math.sqrt;

public class CaisaAndPylons {

    public void run() throws Exception {
        int number = Integer.parseInt(nextLine().split("")[0]);
        String[] numbers = nextLine().split(" ");
        int amountOfDollars = Integer.parseInt(numbers[0]);
        int reminder = 0;
        for (int i = 0; i < numbers.length-1 ; i++) {

            int previous = Integer.parseInt(numbers[i]);
            int current = Integer.parseInt(numbers[i + 1]);
            int diff = (previous + reminder) -(current)  ;
            if (diff < 0) {
                amountOfDollars += Math.abs(diff);
                reminder = 0;
            } else {
                reminder = diff;
            }
        }
        System.out.println(amountOfDollars);

    }
    public void runs() throws Exception {
        Scanner scanner = new Scanner(System.in);
        int number = Integer.parseInt(scanner.nextLine().split(" ")[0]);

        int amountOfDollars = 0;
        int reminder = 0;
        int previous = 0;
        for (int i = 0; i < number; i++) {
            int currentValue = scanner.nextInt();

            int diff = (previous + reminder) - (currentValue);
            if (diff < 0) {
                amountOfDollars += Math.abs(diff);
                reminder = 0;
            } else {
                reminder = diff;
            }
            previous = currentValue;
        }
        System.out.println(amountOfDollars);

    }


    public static void main(String... args) throws Exception {
        br = new BufferedReader(new InputStreamReader(System.in));
        pw = new PrintWriter(new BufferedOutputStream(System.out));
        new CaisaAndPylons().run();
        br.close();
        pw.close();
        System.err.println("\n[Time : " + (System.currentTimeMillis() - startTime) + " ms]");
        long gct = 0, gcc = 0;
        for (GarbageCollectorMXBean garbageCollectorMXBean : ManagementFactory.getGarbageCollectorMXBeans()) {
            gct += garbageCollectorMXBean.getCollectionTime();
            gcc += garbageCollectorMXBean.getCollectionCount();
        }
        System.err.println("[GC time : " + gct + " ms, count = " + gcc + "]");
    }

    static long startTime = System.currentTimeMillis();
    static BufferedReader br;
    static PrintWriter pw;
    StringTokenizer stok;

    String nextToken() throws IOException {
        while (stok == null || !stok.hasMoreTokens()) {
            String s = br.readLine();
            if (s == null) {
                return null;
            }
            stok = new StringTokenizer(s);
        }
        return stok.nextToken();
    }

    void print(byte b) {
        print("" + b);
    }

    void print(int i) {
        print("" + i);
    }

    void print(long l) {
        print("" + l);
    }

    void print(double d) {
        print("" + d);
    }

    void print(char c) {
        print("" + c);
    }

    void print(Object o) {
        if (o instanceof int[]) {
            print(Arrays.toString((int[]) o));
        } else if (o instanceof long[]) {
            print(Arrays.toString((long[]) o));
        } else if (o instanceof char[]) {
            print(Arrays.toString((char[]) o));
        } else if (o instanceof byte[]) {
            print(Arrays.toString((byte[]) o));
        } else if (o instanceof short[]) {
            print(Arrays.toString((short[]) o));
        } else if (o instanceof boolean[]) {
            print(Arrays.toString((boolean[]) o));
        } else if (o instanceof float[]) {
            print(Arrays.toString((float[]) o));
        } else if (o instanceof double[]) {
            print(Arrays.toString((double[]) o));
        } else if (o instanceof Object[]) {
            print(Arrays.toString((Object[]) o));
        } else {
            print("" + o);
        }
    }

    void printsp(int[] a) {
        for (int i = 0, n = a.length; i < n; print(a[i] + " "), i++)
            ;
    }

    void printsp(long[] a) {
        for (int i = 0, n = a.length; i < n; print(a[i] + " "), i++)
            ;
    }

    void print(String s) {
        pw.print(s);
    }

    void println() {
        println("");
    }

    void println(byte b) {
        println("" + b);
    }

    void println(int i) {
        println("" + i);
    }

    void println(long l) {
        println("" + l);
    }

    void println(double d) {
        println("" + d);
    }

    void println(char c) {
        println("" + c);
    }

    void println(Object o) {
        print(o);
        println();
    }

    void println(String s) {
        pw.println(s);
    }

    int nextInt() throws IOException {
        return Integer.parseInt(nextToken());
    }

    long nextLong() throws IOException {
        return Long.parseLong(nextToken());
    }

    double nextDouble() throws IOException {
        return Double.parseDouble(nextToken());
    }

    char nextChar() throws IOException {
        return (char) (br.read());
    }

    String next() throws IOException {
        return nextToken();
    }

    String nextLine() throws IOException {
        return br.readLine();
    }

    int[] readInt(int size) throws IOException {
        int[] array = new int[size];
        for (int i = 0; i < size; i++) {
            array[i] = nextInt();
        }
        return array;
    }

    long[] readLong(int size) throws IOException {
        long[] array = new long[size];
        for (int i = 0; i < size; i++) {
            array[i] = nextLong();
        }
        return array;
    }

    double[] readDouble(int size) throws IOException {
        double[] array = new double[size];
        for (int i = 0; i < size; i++) {
            array[i] = nextDouble();
        }
        return array;
    }

    String[] readLines(int size) throws IOException {
        String[] array = new String[size];
        for (int i = 0; i < size; i++) {
            array[i] = nextLine();
        }
        return array;
    }

    int gcd(int a, int b) {
        if (a == 0)
            return Math.abs(b);
        if (b == 0)
            return Math.abs(a);
        a = Math.abs(a);
        b = Math.abs(b);
        int az = Integer.numberOfTrailingZeros(a), bz = Integer.numberOfTrailingZeros(b);
        a >>>= az;
        b >>>= bz;
        while (a != b) {
            if (a > b) {
                a -= b;
                a >>>= Integer.numberOfTrailingZeros(a);
            } else {
                b -= a;
                b >>>= Integer.numberOfTrailingZeros(b);
            }
        }
        return (a << Math.min(az, bz));
    }

    long gcd(long a, long b) {
        if (a == 0)
            return Math.abs(b);
        if (b == 0)
            return Math.abs(a);
        a = Math.abs(a);
        b = Math.abs(b);
        int az = Long.numberOfTrailingZeros(a), bz = Long.numberOfTrailingZeros(b);
        a >>>= az;
        b >>>= bz;
        while (a != b) {
            if (a > b) {
                a -= b;
                a >>>= Long.numberOfTrailingZeros(a);
            } else {
                b -= a;
                b >>>= Long.numberOfTrailingZeros(b);
            }
        }
        return (a << Math.min(az, bz));
    }

    boolean isPrime(int v) {
        if (v <= 1) {
            return false;
        }
        if (v <= 3) {
            return true;
        }
        if (((v & 1) == 0) || ((v % 3) == 0)) {
            return false;
        }
        for (int m = 5, n = (int) sqrt(v); m <= n; m += 6) {
            if (((v % m) == 0) || ((v % (m + 2)) == 0)) {
                return false;
            }
        }
        return true;
    }

    void rshuffle(int[] a) { // RANDOM shuffle
        Random r = new Random();
        for (int i = a.length - 1, j, t; i >= 0; j = r.nextInt(a.length), t = a[i], a[i] = a[j], a[j] = t, i--)
            ;
    }

    void qshuffle(int[] a) { // QUICK shuffle
        int m = new Random().nextInt(10) + 2;
        for (int i = 0, n = a.length, j = m % n, t; i < n; t = a[i], a[i] = a[j], a[j] = t, i++, j = (i * m) % n)
            ;
    }

    void shuffle(long[] a) {
        Random r = new Random();
        for (int i = a.length - 1; i >= 0; i--) {
            int j = r.nextInt(a.length);
            long t = a[i];
            a[i] = a[j];
            a[j] = t;
        }
    }

    void shuffle(Object[] a) {
        Random r = new Random();
        for (int i = a.length - 1; i >= 0; i--) {
            int j = r.nextInt(a.length);
            Object t = a[i];
            a[i] = a[j];
            a[j] = t;
        }
    }

    int[] sort(int[] a) {
        final int SHIFT = 16, MASK = (1 << SHIFT) - 1, SIZE = (1 << SHIFT) + 1;
        int n = a.length, ta[] = new int[n], ai[] = new int[SIZE];
        for (int i = 0; i < n; ai[(a[i] & MASK) + 1]++, i++)
            ;
        for (int i = 1; i < SIZE; ai[i] += ai[i - 1], i++)
            ;
        for (int i = 0; i < n; ta[ai[a[i] & MASK]++] = a[i], i++)
            ;
        int[] t = a;
        a = ta;
        ta = t;
        ai = new int[SIZE];
        for (int i = 0; i < n; ai[(a[i] >> SHIFT) + 1]++, i++)
            ;
        for (int i = 1; i < SIZE; ai[i] += ai[i - 1], i++)
            ;
        for (int i = 0; i < n; ta[ai[a[i] >> SHIFT]++] = a[i], i++)
            ;
        return ta;
    }

    void flush() {
        pw.flush();
    }

    void pause() {
        flush();
        System.console().readLine();
    }

}
