#include <iostream>
using namespace std;
typedef long long lll;
int n,a[1001],i,k,mini,rj;
int main(){
	cin>>n;
	if (n==1) {cout<<"0"<<endl; return 0;}
	for (i=0; i<n; i++) cin>>a[i];
	mini=a[0];
	for (i=1; i<n; i++)
	{
		if (a[i]>a[i-1]) continue;
		k=a[i-1]-mini;
		if (k>rj) rj=k;
		mini=a[i];
		}
	if (a[n-1]>a[n-2])
	{
	k=a[n-1]-mini;
	if (k>rj) rj=k;
		}
	cout<<rj<<endl;
	return 0;
}