import java.util.ArrayList;
import java.util.Arrays;
import java.util.Scanner;

public class Main {
	MyScanner sc = new MyScanner();
	Scanner sc2 = new Scanner(System.in);
	final int MOD = 1000000007;
	int[] dx = { 1, 0, 0, -1 };
	int[] dy = { 0, 1, -1, 0 };
	int n, m;
	double[][] dis;
	double max = 0;

	void run() {
		n = sc.nextInt();
		m = sc.nextInt();
		dis = new double[n][3];
		for (int i = 0; i < n; i++) {
			dis[i][0] = sc.nextDouble();
			dis[i][1] = sc.nextDouble();
			dis[i][2] = sc.nextDouble();
		}
		dfs(0, new ArrayList<Integer>());
		System.out.println(max);
	}

	void dfs(int index, ArrayList<Integer> select) {
		if (select.size() == m) {
			double d = 0;
			for (int i = 0; i < m; i++) {
				for (int j = i + 1; j < m; j++) {
					d += ((dis[select.get(i)][0] - dis[select.get(j)][0])
							* (dis[select.get(i)][0] - dis[select.get(j)][0])
							+ (dis[select.get(i)][1] - dis[select.get(j)][1])
							* (dis[select.get(i)][1] - dis[select.get(j)][1]) + (dis[select
							.get(i)][2] - dis[select.get(j)][2])
							* (dis[select.get(i)][2] - dis[select.get(j)][2]));
				}
			}
			max = Math.max(max, d);
			return;
		}
		if (index >= n) {
			return;
		}
		select.add(index);
		dfs(index + 1, select);
		select.remove(select.size() - 1);
		dfs(index + 1, select);
	}

	public static void main(String[] args) {
		new Main().run();
	}

	void debug(Object... o) {
		System.out.println(Arrays.deepToString(o));
	}

	void debug2(int[][] array) {
		for (int i = 0; i < array.length; i++) {
			for (int j = 0; j < array[i].length; j++) {
				System.out.print(array[i][j]);
			}
			System.out.println();
		}
	}

	boolean inner(int h, int w, int limH, int limW) {
		return 0 <= h && h < limH && 0 <= w && w < limW;
	}

	void swap(int[] x, int a, int b) {
		int tmp = x[a];
		x[a] = x[b];
		x[b] = tmp;
	}

	// find minimum i (a[i] >= border)
	int lower_bound(int a[], int border) {
		int l = -1;
		int r = a.length;

		while (r - l > 1) {
			int mid = (l + r) / 2;
			if (border <= a[mid]) {
				r = mid;
			} else {
				l = mid;
			}
		}
		// r = l + 1
		return r;
	}

	class MyScanner {
		int nextInt() {
			try {
				int c = System.in.read();
				while (c != '-' && (c < '0' || '9' < c))
					c = System.in.read();
				if (c == '-')
					return -nextInt();
				int res = 0;
				do {
					res *= 10;
					res += c - '0';
					c = System.in.read();
				} while ('0' <= c && c <= '9');
				return res;
			} catch (Exception e) {
				return -1;
			}
		}

		double nextDouble() {
			return Double.parseDouble(next());
		}

		long nextLong() {
			return Long.parseLong(next());
		}

		String next() {
			try {
				StringBuilder res = new StringBuilder("");
				int c = System.in.read();
				while (Character.isWhitespace(c))
					c = System.in.read();
				do {
					res.append((char) c);
				} while (!Character.isWhitespace(c = System.in.read()));
				return res.toString();
			} catch (Exception e) {
				return null;
			}
		}

		int[] nextIntArray(int n) {
			int[] in = new int[n];
			for (int i = 0; i < n; i++) {
				in[i] = nextInt();
			}
			return in;
		}

		int[][] nextInt2dArray(int n, int m) {
			int[][] in = new int[n][m];
			for (int i = 0; i < n; i++) {
				in[i] = nextIntArray(m);
			}
			return in;
		}

		double[] nextDoubleArray(int n) {
			double[] in = new double[n];
			for (int i = 0; i < n; i++) {
				in[i] = nextDouble();
			}
			return in;
		}

		long[] nextLongArray(int n) {
			long[] in = new long[n];
			for (int i = 0; i < n; i++) {
				in[i] = nextLong();
			}
			return in;
		}
	}
}

Measured memory_bytes: 24380