#include<bits/stdc++.h>
using namespace std;

int n,mx,mn = INT_MAX, a[1000005];

void read(int& x){
	x = 0;
	char c = getchar();
	bool neg = 0;
	while(!isdigit(c) && c != '-')
		c = getchar();
	if(c == '-')
		neg = 1, c = getchar();
	while(isdigit(c))
		x = 10 * x + (c ^ 48), c = getchar();
	if(neg)
		x = -x;
}

int main(){
	read(n);
	for(int i = 1; i <= n; i++)
		read(a[i]), mx = max(mx,a[i]), mn = min(mn,a[i]);
	
	printf("%d",max({abs(a[n] - a[1]), a[n] - mn, mx - a[1]}));
	
	return 0;
}