import static java.util.Arrays.binarySearch;

import java.io.IOException;
import java.util.TreeSet;

public class Main {

	public static void main(String[] args) {
		int N = nextInt();
		int B = nextInt();
		int[] xs = new int[N];
		int[] ys = new int[N];
		int[] point = new int[N];
		for (int i = 0; i < N; i++) {
			xs[i] = nextInt();
			ys[i] = nextInt();
			point[i] = nextInt();
		}

		TreeSet<Integer> xTreeSet = new TreeSet<Integer>();
		TreeSet<Integer> yTreeSet = new TreeSet<Integer>();

		for (int i = 0; i < N; i++) {
			xTreeSet.add(xs[i]);
			yTreeSet.add(ys[i]);
		}
		xTreeSet.add((int) Integer.MAX_VALUE);
		xTreeSet.add((int) Integer.MIN_VALUE);
		yTreeSet.add((int) Integer.MAX_VALUE);
		yTreeSet.add((int) Integer.MIN_VALUE);

		Integer[] xIntegers = xTreeSet.toArray(new Integer[0]);
		Integer[] yIntegers = yTreeSet.toArray(new Integer[0]);

		int w = xIntegers.length;
		int h = yIntegers.length;

		int[][] treasures = new int[h + 1][w + 1];
		int[][] tPoints = new int[h + 1][w + 1];

		for (int i = 0; i < N; i++) {
			int x = binarySearch(xIntegers, xs[i]);
			int y = binarySearch(yIntegers, ys[i]);
			treasures[y + 1][x + 1]++;
			tPoints[y + 1][x + 1] += point[i];
		}

		for (int i = 0; i < h; i++) {
			for (int j = 0; j < w; j++) {
				treasures[i + 1][j + 1] += treasures[i + 1][j] + treasures[i][j + 1] - treasures[i][j];
				tPoints[i + 1][j + 1] += tPoints[i + 1][j] + tPoints[i][j + 1] - tPoints[i][j];
			}
		}

		int tMax = 0;
		for (int x1 = 0; x1 < w; x1++) {
			for (int x2 = x1 + 1; x2 < w + 1; x2++) {
				int y1 = 0;
				int y2 = 1;
				while (y2 < h + 1) {
					int tNum = treasures[y2][x2] - treasures[y1][x2] - treasures[y2][x1] + treasures[y1][x1];
					int pointNum = tPoints[y2][x2] - tPoints[y1][x2] - tPoints[y2][x1] + tPoints[y1][x1];
					if (pointNum <= B) {
						tMax = Math.max(tMax, tNum);
						y2++;
					} else {
						y1++;
					}
				}

			}
		}
		System.out.println(tMax);
	}

	static int nextInt() {
		int c;
		try {
			c = System.in.read();
			while (c != '-' && (c < '0' || c > '9'))
				c = System.in.read();
			if (c == '-')
				return -nextInt();
			int res = 0;
			while (c >= '0' && c <= '9') {
				res = res * 10 + c - '0';
				c = System.in.read();
			}
			return res;
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return -1;
	}

}