hdu1421

/**/
#include <cstdio>
#include <cstring>
#include <cmath>
#include <cctype>
#include <iostream>
#include <algorithm>
#include <map>
#include <set>
#include <vector>
#include <string>
#include <stack>
#include <queue>

typedef long long LL;
using namespace std;

int n, k;
int dp[2005][1005];
int a[2005];

int main()
{
	//freopen("in.txt", "r", stdin);
	//freopen("out.txt", "w", stdout);

	while(scanf("%d %d", &n, &k) == 2){
		for (int i = 1; i <= n; i++){
			scanf("%d", &a[i]);
		}
		sort(a + 1, a + n + 1);
		memset(dp, 0x3f3f3f3f, sizeof(dp));
		for (int i = 0; i <= n; i++) dp[i][0] = 0;
		for (int i = 2; i <= n; i++){
			for (int j = 1; j * 2 <= i; j++){
				dp[i][j] = min(dp[i - 2][j - 1] + (a[i] - a[i - 1]) * (a[i] - a[i - 1]), dp[i - 1][j]);
			}
		}
		printf("%d\n", dp[n][k]);
	}

	return 0;
}
/**/