#include "bits/stdc++.h"

using namespace std;

void solve(void)
{
	int n;
	cin >> n;
	vector<long> ys(n);
	for (int i = 0; i < n; i++)
	{
		cin >> ys[i];
	}
	sort(ys.begin(), ys.end());
	long ans = ys[1] - ys[0], p = ys[1];
	for (int i = 2; i < n-1; i++)
	{
		if (ys[i] - p >= ys[i+1] - ys[i])
		{
			ans += ys[i + 1] - ys[i];
			p = ys[i + 1];
			i++;
		}
		else
		{
			ans += ys[i] - p;
		}
	}
	ans += ys.back() - p;
	cout << ans << endl;
}

int main()
{
	solve();
	//cout << "yui(*-v・)yui" << endl;
	return 0;
}