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

 class Main{

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

		int n = Integer.parseInt(br.readLine());
		int[] in = new int[n];
		int max = Integer.MIN_VALUE;
		int mini = 0;
		int maxj=0;
		boolean con=false;
		
		for (int i = 0; i < n; i++)
			in[i] = Integer.parseInt(br.readLine());
		
		for (int i = 0; i < n - 1; i++) {
			if (in[i] > in[mini])continue;
			for (int j = i + 1; j < n; j++){
				if(i!=0&&con&&i<maxj){
					mini=i;
					max=in[maxj]-in[i];
					break;}
				else if(max+in[i]<in[j]){
					max=in[j]-in[i];
					mini=i;
					maxj=j;
					con=false;
				}
			}con=true;
		}
		System.out.println(max);
	}}
/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