import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int max=0;
        int n = in.nextInt();
        int[] a = new int[n];
        for(int i=0; i < n; i++){
            a[i] = in.nextInt();
        }
        int c[]= new int[10];
        for(int i=0;i<n;i++){
            for(int j=i+1;j<n;j++){
                c[i]=a[i]-a[j];
                Math.abs(c[i]);
            }
        }
        // your code goes here
        for(int i=0;i<n;i++)
            {
            if(c[i]>c[i+1])
                {
                max= c[i];
            }
        }
        System.out.print(max);
    }
}