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