#include <bits/stdc++.h>
#define rep(i, a) for (int i = 0; i < (a); i++)
#define rep2(i, a, b) for (int i = (a); i < (b); i++)
#define repr(i, a) for (int i = (a) - 1; i >= 0; i--)
#define repr2(i, a, b) for (int i = (b) - 1; i >= (a); i--)
using namespace std;
typedef long long ll;
const ll inf = 1e9;
const ll mod = 1e9 + 7;

ll N, B;
ll X[400], Y[400], P[400];
ll sum[500][500], num[500][500];

ll calc(ll s[500][500], int x1, int y1, int x2, int y2) {
	return s[x2][y2] - s[x2][y1] - s[x1][y2] + s[x1][y1];
}

int main() {
	cin >> N >> B;
	rep (i, N) cin >> X[i] >> Y[i] >> P[i];

	vector<ll> xs, ys;
	rep (i, N) {
		xs.push_back(X[i]);
		ys.push_back(Y[i]);
	}
	sort(xs.begin(), xs.end());
	sort(ys.begin(), ys.end());
	xs.erase(unique(xs.begin(), xs.end()), xs.end());
	ys.erase(unique(ys.begin(), ys.end()), ys.end());

	rep (i, N) {
		X[i] = lower_bound(xs.begin(), xs.end(), X[i]) - xs.begin();
		Y[i] = lower_bound(ys.begin(), ys.end(), Y[i]) - ys.begin();
	}

	int W = xs.size() + 2;
	int H = ys.size() + 2;

	rep (i, N) {
		sum[X[i] + 1][Y[i] + 1] += P[i];
		num[X[i] + 1][Y[i] + 1]++;
	}
	rep (i, W + 1) rep (j, H + 1) {
		sum[i][j + 1] += sum[i][j];
		num[i][j + 1] += num[i][j];
	}
	rep (j, H + 1) rep (i, W + 1) {
		sum[i + 1][j] += sum[i][j];
		num[i + 1][j] += num[i][j];
	}

	ll ans = 0;

	rep (i, W * H) {
		int x1 = i % W;
		int y1 = i / W;
		int x2 = W;
		rep2 (y2, y1 + 1, H) {
			while (x2 > x1 && calc(sum, x1, y1, x2, y2) > B) x2--;
			ans = max(ans, calc(num, x1, y1, x2, y2));
		}
	}
	cout << ans << endl;

	return 0;
}