

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {

	public static void main(String[] args) throws NumberFormatException, IOException {
		// TODO ?????????????????????????????????????????????
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

		//??\?????¨
		int n = Integer.parseInt(br.readLine());

		int[] price = new int[n];
		for(int i = 0; i < n; i++){
			price[i] = Integer.parseInt(br.readLine());
		}

		int maxProfit = Integer.MIN_VALUE;
		int prevBuy = Integer.MAX_VALUE;

		for(int i = 0; i < n - 1; i++){
			int tmpHigh = 0;

			if(price[i] >= prevBuy){
				continue;
			}
			prevBuy = price[i];
			
			for(int j = i + 1; j < n; j++){
				if(price[j] > tmpHigh){
					tmpHigh = price[j];
				}
			}

			if(tmpHigh - price[i] > maxProfit){
				maxProfit = tmpHigh - price[i];
			}
		}


		System.out.println(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