#include <map>
#include <set>
#include <list>
#include <queue>
#include <stack>
#include <vector>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <algorithm>

using namespace std;

const int N = 2010;

int dp[N][1010];
int th[N];

int main()
{
	int n, k;
	while (~scanf("%d%d", &n, &k))
	{
		memset (dp, 0, sizeof(dp));
		for (int i = 1; i <= n; ++i)
		{
			scanf("%d", &th[i]);
		}
		sort (th + 1, th + n + 1);
		for (int i = 1; i <= n; ++i)
		{
			for (int j = 1; 2 * j <= i; ++j)
			{
				if (i == 2 * j)
				{
					dp[i][j] = dp[i - 2][j - 1] + (th[i] - th[i - 1]) * (th[i] - th[i - 1]);
				}
				else if (i > 2 * j)
				{
					dp[i][j] = min(dp[i - 1][j], dp[i - 2][j - 1] + (th[i] - th[i - 1]) * (th[i] - th[i - 1]));
				}
			}
		}
		printf("%d\n", dp[n][k]);
	}
	return 0;
}