import java.util.Scanner;

class Main{
    public static void main(String[] args){
        Scanner scan = new Scanner(System.in);

        int n = Integer.parseInt(scan.nextLine());
        double Rj = 0;
        double Ri = 0;
        double newR;
        double maxProfit = -1000000000;
        double tmpProfit = -1000000000;
        double tmp = 0;

        int value;
        for (int i=0; i<n; i++){
            newR = Integer.parseInt(scan.nextLine());
            if (i == 0){
                Rj = newR;
                Ri = newR;
                continue;
            }
            if (newR < Ri){
                tmp = newR - Ri;
                if (tmp > tmpProfit)
                    tmpProfit = tmp;
                Ri = newR;
                Rj = newR;
                continue;
            }
            if (newR >= Rj){
                Rj = newR;
                tmp = Rj - Ri;
                if (tmp > maxProfit)
                    maxProfit = tmp;
                continue;
            }
        }

        if (tmpProfit > maxProfit)
            maxProfit = tmpProfit;
        else if (tmpProfit == maxProfit)
            maxProfit = 0;

        System.out.println((int)(maxProfit));
    }
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz