#include <vector>
#include <climits>
#include <algorithm>
#include <iostream>

using namespace std;

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);

	int num, val, ans = INT_MAX - 101;
	int lower, upper;
	vector<int> lst { INT_MIN + 100, INT_MAX - 100 };
	vector<int>::iterator itIn, itRef;

	cin >> num;

	while(num)
	{
		--num;

		cin >> val;
		itIn = find_if(lst.begin(), lst.end(), [=](int l){ return val < l; });
		itRef = lst.insert(itIn, val);

		lower = *(itRef + 0) - *(itRef - 1);
		upper = *(itRef + 1) - *(itRef + 0);

		if(lower == 0)
		{
			lst.erase(itRef);

			continue;
		}

		if(lower > 0)
		{
			ans = min(min(lower, upper), ans);
		}
	}

	cout << ans << endl;

	return 0;
}