import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.Arrays;
import java.util.StringTokenizer;

public class Main {
    public static void main(String[] args) {
        final BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        final BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        try {
            int T = 1;
            for (int i = 0; i < T; ++i) {
                Runner runner = new Runner(br, bw);
                runner.run();
                runner.flush();
            }
            br.close();
            bw.close();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}

class Solution {
    final int N;
    final int[] prices;

    Solution(int N, int[] prices) {
        this.N = N;
        this.prices = prices;
    }

    public int solution() {
        int[] minValue = new int[N];
        int[] maxValue = new int[N];

        minValue[0] = prices[0];
        for (int i = 1; i < N; ++i)
            minValue[i] = Math.min(minValue[i - 1], prices[i]);

        maxValue[N - 1] = prices[N - 1];
        for (int i = N - 2; i >= 0; --i)
            maxValue[i] = Math.max(maxValue[i + 1], prices[i]);

        int maxProfit = 0;
        for (int i = 0; i < N; ++i) {
            maxProfit = Math.max(maxProfit, maxValue[i] - minValue[i]);
        }
        return maxProfit;
    }
}

class Runner {
    final Reader reader;
    final BufferedWriter bw;

    final int N;
    final int[] prices;

    Runner(BufferedReader br, BufferedWriter bw) {
        this.reader = new Reader(br);
        this.bw = bw;
        try {
            this.N = Integer.parseInt(br.readLine());
            this.prices = reader.readInts();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    public void flush() {
        try {
            bw.write('\n');
            bw.flush();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    public void run() throws IOException {
        var res = new Solution(N, prices).solution();
        bw.write(String.valueOf(res));
    }
}

class Reader {
    private BufferedReader br;

    public Reader(BufferedReader br) {
        this.br = br;
    }

    public int[] readInts() throws IOException {
        StringTokenizer st = new StringTokenizer(br.readLine(), " ");
        int cnt = st.countTokens();
        int[] ints = new int[cnt];
        for (int i = 0; i < cnt; ++i) {
            ints[i] = Integer.parseInt(st.nextToken());
        }
        return ints;
    }

    public long[] readLongs() throws IOException {
        StringTokenizer st = new StringTokenizer(br.readLine(), " ");
        int cnt = st.countTokens();
        long[] longs = new long[cnt];
        for (int i = 0; i < cnt; ++i) {
            longs[i] = Long.parseLong(st.nextToken());
        }
        return longs;
    }

    public int[][] readIntArrays() throws IOException {
        return br.lines().map(s -> Arrays.stream(s.split(" "))
                .mapToInt(Integer::parseInt)
                .toArray())
                .toArray(int[][]::new);
    }
}