#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using namespace atcoder;
#define rep(i, n) REP(i, 0, n)
#define REP(i, s, e) for (ll i = (s); i < (ll)(e); i++)
#define repr(i, n) REPR(i, n, 0)
#define REPR(i, s, e) for (ll i = (ll)(s - 1); i >= (ll)(e); i--)
#define all(r) r.begin(), r.end()
#define rall(r) r.rbegin(), r.rend()

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;

template <typename T, typename U>
T chmax(T& a, const U& b) {
    if (a >= b) return false;
    a = b;
    return true;
}
template <typename T, typename U>
T chmin(T& a, const U& b) {
    if (a <= b) return false;
    a = b;
    return true;
}

void yes_no(bool f, string yes = "Yes", string no = "No") { cout << (f ? yes : no) << "\n"; }

template <typename T>
T getSum2D(const vector<vector<T>>& sum, int y1, int y2, int x1, int x2) {
    // y1--;
    // x1--;
    return sum[y2][x2] - sum[y1][x2] - sum[y2][x1] + sum[y1][x1];
}
template <typename T>
void preCalcSum2D(vector<vector<T>>& sum) {
    int H = sum.size(), W = sum[0].size();
    for (int i = 1; i < H; i++) {
        for (int j = 0; j < W; j++) {
            sum[i][j] += sum[i - 1][j];
        }
    }
    for (int i = 0; i < H; i++) {
        for (int j = 1; j < W; j++) {
            sum[i][j] += sum[i][j - 1];
        }
    }
}

template <typename T>
pair<vector<T>, vector<T>> zaatu(vector<T> a) {
    int n = a.size();
    auto rev = a;
    sort(all(rev));
    rev.erase(unique(all(rev)), rev.end());
    vector<T> z(n);
    rep(i, n) z[i] = lower_bound(all(rev), a[i]) - rev.begin();
    return {z, rev};
}

void solve() {
    ll n, b;
    cin >> n >> b;

    using T = tuple<ll, ll, ll>;
    vector<T> a(n);
    vl vx, vy;
    rep(i, n) {
        ll x, y, z;
        cin >> x >> y >> z;
        a[i] = {x, y, z};
        vx.emplace_back(x);
        vx.emplace_back(x - 1);
        vx.emplace_back(x + 1);

        vy.emplace_back(y);
        vy.emplace_back(y - 1);
        vy.emplace_back(y + 1);
    }
    auto [mx, rx] = zaatu(vx);
    auto [my, ry] = zaatu(vy);
    int h = ry.size() + 5;
    int w = rx.size() + 5;

    vector<vl> num(h, vl(w));
    vector<vl> score(h, vl(w));
    rep(i, n) {
        num[my[3 * i]][mx[3 * i]]++;
        score[my[3 * i]][mx[3 * i]] += get<2>(a[i]);
    }
    preCalcSum2D(num);
    preCalcSum2D(score);
    ll ans = -1e18;
    rep(ly, h) REP(ry, ly + 1, h) {
        int rx = 0;
        auto init_state = [&](int lx) {
            rx = lx;
        };
        auto judge_r = [&](int lx, int rx) {
            return getSum2D(score, ly, ry, lx, rx) <= b;
        };
        auto add_r = [&](int r) {
        };
        auto update = [&](int lx, int rx) {
            chmax(ans, getSum2D(num, ly, ry, lx, rx));
        };
        auto erace_l = [&](int l) {
        };
        rep(lx, n) {
            if (rx < lx) init_state(lx);
            while (rx < w && judge_r(lx, rx + 1)) {
                add_r(rx);
                rx++;
            }
            update(lx, rx);
            erace_l(lx);
        }
    }
    cout << ans << "\n";
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int t = 1;
    // multi-testcase
    // cin >> t;
    rep(ti, t) solve();
    return 0;
}