#include<bits/stdc++.h>
using namespace std;
int n;
int a[1000000+5];
int main()
{
	int maxx=-1,max_id,minn=INT_MAX,min_id;
	scanf("%d",&n);
	for(int i=1;i<=n;i++)
	{
		scanf("%d",&a[i]);
		if(maxx<a[i])
		{
			maxx=a[i];
			max_id=i;
		}
		if(minn>a[i])
		{
			minn=a[i];
			min_id=i;
		}
	}
	int ans=abs(a[1]-a[n]);
	if(min_id==1||max_id==n)
		ans=maxx-minn;
	else
		ans=max({ans,a[max_id]-a[1],a[n]-a[min_id]});
	printf("%d",ans);
	return 0;
}