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 n = in.nextInt();
        int[] a = new int[n];
        int[] d = new int[n];
        int a_i,diff=0;
        for(a_i=0; a_i < n; a_i++){
            a[a_i] = in.nextInt();
        }
        int k=0;
        for(a_i=0; a_i < n; a_i++)
            {for(int a_j=a_i+1;a_j<n;a_j++)
        {
                 d[k]= Math.abs(a[a_i]-a[a_j]); 
                k++;
        }}
        for(a_i=0;a_i<n-1;a_i++)
        {
            if(d[a_i]>d[a_i+1]){
                diff=d[a_i+1];
            }
        }
        System.out.println(diff);
    }
}