#include <bits/stdc++.h>

int main()
{
	int N;
	scanf("%d", &N);
	std::vector<int64_t> Y(N);
	for (auto& e: Y) scanf("%lld", &e);
	std::sort(Y.begin(), Y.end());
	std::vector<int64_t> dp(N + 1);
	dp[1] = 1ll << 60;
	for (int i{1}; i < N; i++)
	{
		dp[i + 1] = dp[i - 1] + Y[i] - Y[i - 1];
		if (i > 1)
			dp[i + 1] = std::min(dp[i + 1], dp[i - 2] + Y[i] - Y[i - 2]);
	}
	printf("%lld\n", dp.back());

	return 0;
}