import java.util.*;
class Main{
    public static void main(String args[]){
        Scanner sc=new Scanner(System.in);
        if(!s.hasNextInt()){
            System.out.println("Invalid input");
            return;
        }
        int n=sc.nextInt();
        if(n<=0){
            System.out.println("Invalid input");
            return;
        }
        int arr[]=new int[n];
        for(int i=0;i<n;i++){
            arr[i]=sc.nextInt();
        }
        int count=0;
        int b=0;
        for(int i=0;i<n;i++){
            int sum=0;
            for(int j=i+1;j<n;j++){
                
                sum=arr[j]-arr[i];
                if(sum>count){
                    b++;
                    count=sum;
                }
        }
        }
        System.out.println(count);
    }
}