//Question 1

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

int main()
{
	int n, maxi = INT_MIN, mini = INT_MAX;
	int a[100009], ans = INT_MIN;
	pair<int, int> bucket[100009];
	double avg;

	cin>>n;
	for(int i=0; i<n; i++)
	{
		cin>>a[i];
		maxi = max(maxi, a[i]);
		mini = min(mini, a[i]);
		bucket[i] = make_pair(INT_MAX, INT_MIN);
	}

	avg = (maxi - mini)*1.0/(n-1);
	for(int i=0; i<n; i++)
	{
		int x = (a[i] - mini)/avg;
		bucket[x].first = min(bucket[x].first, a[i]);
		bucket[x].second = max(bucket[x].second, a[i]);
	}

	int prev = bucket[0].second;
	for(int i=1; i<n; i++)
	{
		if(bucket[i].first == INT_MAX)
			continue;
		ans = max(ans, bucket[i].first - prev);
		prev = bucket[i].second;
	}

	printf("%d\n", ans);
}