#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <chrono>
#include <cmath>
#include <complex>
#include <deque>
#include <forward_list>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iostream>
#include <limits>
#include <list>
#include <map>
#include <memory>
#include <numeric>
#include <optional>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <tuple>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
using namespace std;
using lint = long long;
using pint = pair<int, int>;
using plint = pair<lint, lint>;
struct fast_ios { fast_ios(){ cin.tie(nullptr), ios::sync_with_stdio(false), cout << fixed << setprecision(20); }; } fast_ios_;
#define ALL(x) (x).begin(), (x).end()
#define FOR(i, begin, end) for(int i=(begin),i##_end_=(end);i<i##_end_;i++)
#define IFOR(i, begin, end) for(int i=(end)-1,i##_begin_=(begin);i>=i##_begin_;i--)
#define REP(i, n) FOR(i,0,n)
#define IREP(i, n) IFOR(i,0,n)
template <typename T> bool chmax(T &m, const T q) { return m < q ? (m = q, true) : false; }
template <typename T> bool chmin(T &m, const T q) { return m > q ? (m = q, true) : false; }
const std::vector<std::pair<int, int>> grid_dxs{{1, 0}, {-1, 0}, {0, 1}, {0, -1}};
int floor_lg(long long x) { return x <= 0 ? -1 : 63 - __builtin_clzll(x); }
template <class T1, class T2> T1 floor_div(T1 num, T2 den) { return (num > 0 ? num / den : -((-num + den - 1) / den)); }
template <class T1, class T2> std::pair<T1, T2> operator+(const std::pair<T1, T2> &l, const std::pair<T1, T2> &r) { return std::make_pair(l.first + r.first, l.second + r.second); }
template <class T1, class T2> std::pair<T1, T2> operator-(const std::pair<T1, T2> &l, const std::pair<T1, T2> &r) { return std::make_pair(l.first - r.first, l.second - r.second); }
template <class T> std::vector<T> sort_unique(std::vector<T> vec) { sort(vec.begin(), vec.end()), vec.erase(unique(vec.begin(), vec.end()), vec.end()); return vec; }
template <class T> int arglb(const std::vector<T> &v, const T &x) { return std::distance(v.begin(), std::lower_bound(v.begin(), v.end(), x)); }
template <class T> int argub(const std::vector<T> &v, const T &x) { return std::distance(v.begin(), std::upper_bound(v.begin(), v.end(), x)); }
template <class IStream, class T> IStream &operator>>(IStream &is, std::vector<T> &vec) { for (auto &v : vec) is >> v; return is; }

template <class OStream, class T> OStream &operator<<(OStream &os, const std::vector<T> &vec);
template <class OStream, class T, size_t sz> OStream &operator<<(OStream &os, const std::array<T, sz> &arr);
template <class OStream, class T, class TH> OStream &operator<<(OStream &os, const std::unordered_set<T, TH> &vec);
template <class OStream, class T, class U> OStream &operator<<(OStream &os, const pair<T, U> &pa);
template <class OStream, class T> OStream &operator<<(OStream &os, const std::deque<T> &vec);
template <class OStream, class T> OStream &operator<<(OStream &os, const std::set<T> &vec);
template <class OStream, class T> OStream &operator<<(OStream &os, const std::multiset<T> &vec);
template <class OStream, class T> OStream &operator<<(OStream &os, const std::unordered_multiset<T> &vec);
template <class OStream, class T, class U> OStream &operator<<(OStream &os, const std::pair<T, U> &pa);
template <class OStream, class TK, class TV> OStream &operator<<(OStream &os, const std::map<TK, TV> &mp);
template <class OStream, class TK, class TV, class TH> OStream &operator<<(OStream &os, const std::unordered_map<TK, TV, TH> &mp);
template <class OStream, class... T> OStream &operator<<(OStream &os, const std::tuple<T...> &tpl);

template <class OStream, class T> OStream &operator<<(OStream &os, const std::vector<T> &vec) { os << '['; for (auto v : vec) os << v << ','; os << ']'; return os; }
template <class OStream, class T, size_t sz> OStream &operator<<(OStream &os, const std::array<T, sz> &arr) { os << '['; for (auto v : arr) os << v << ','; os << ']'; return os; }
template <class... T> std::istream &operator>>(std::istream &is, std::tuple<T...> &tpl) { std::apply([&is](auto &&... args) { ((is >> args), ...);}, tpl); return is; }
template <class OStream, class... T> OStream &operator<<(OStream &os, const std::tuple<T...> &tpl) { os << '('; std::apply([&os](auto &&... args) { ((os << args << ','), ...);}, tpl); return os << ')'; }
template <class OStream, class T, class TH> OStream &operator<<(OStream &os, const std::unordered_set<T, TH> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <class OStream, class T> OStream &operator<<(OStream &os, const std::deque<T> &vec) { os << "deq["; for (auto v : vec) os << v << ','; os << ']'; return os; }
template <class OStream, class T> OStream &operator<<(OStream &os, const std::set<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <class OStream, class T> OStream &operator<<(OStream &os, const std::multiset<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <class OStream, class T> OStream &operator<<(OStream &os, const std::unordered_multiset<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <class OStream, class T, class U> OStream &operator<<(OStream &os, const std::pair<T, U> &pa) { return os << '(' << pa.first << ',' << pa.second << ')'; }
template <class OStream, class TK, class TV> OStream &operator<<(OStream &os, const std::map<TK, TV> &mp) { os << '{'; for (auto v : mp) os << v.first << "=>" << v.second << ','; os << '}'; return os; }
template <class OStream, class TK, class TV, class TH> OStream &operator<<(OStream &os, const std::unordered_map<TK, TV, TH> &mp) { os << '{'; for (auto v : mp) os << v.first << "=>" << v.second << ','; os << '}'; return os; }
#ifdef HITONANODE_LOCAL
const string COLOR_RESET = "\033[0m", BRIGHT_GREEN = "\033[1;32m", BRIGHT_RED = "\033[1;31m", BRIGHT_CYAN = "\033[1;36m", NORMAL_CROSSED = "\033[0;9;37m", RED_BACKGROUND = "\033[1;41m", NORMAL_FAINT = "\033[0;2m";
#define dbg(x) std::cerr << BRIGHT_CYAN << #x << COLOR_RESET << " = " << (x) << NORMAL_FAINT << " (L" << __LINE__ << ") " << __FILE__ << COLOR_RESET << std::endl
#define dbgif(cond, x) ((cond) ? std::cerr << BRIGHT_CYAN << #x << COLOR_RESET << " = " << (x) << NORMAL_FAINT << " (L" << __LINE__ << ") " << __FILE__ << COLOR_RESET << std::endl : std::cerr)
#else
#define dbg(x) ((void)0)
#define dbgif(cond, x) ((void)0)
#endif

template <class Int> class wavelet_matrix {

    class bit_vector {
        static constexpr int WSIZE = 64;
        int n = 0;
        int cnt0 = 0;
        std::vector<uint64_t> bits;
        std::vector<int> count_cumsum; // need build()

    public:
        bit_vector(int n_) : n(n_), cnt0(n_) {
            assert(n >= 0);
            bits.assign((n + WSIZE - 1) / WSIZE, 0);
        }

        int size() const { return n; }

        void set(int i) {
            assert(0 <= i and i < n);
            bits[i / WSIZE] |= (1ULL << (i % WSIZE));
        }

        void reset(int i) {
            assert(0 <= i and i < n);
            bits[i / WSIZE] &= ~(1ULL << (i % WSIZE));
        }

        void build() {
            cnt0 = n;
            for (int i = 0; i < (int)bits.size(); ++i) cnt0 -= std::popcount(bits[i]);
            count_cumsum.assign(bits.size(), 0);
            for (int i = 1; i < (int)bits.size(); ++i) {
                count_cumsum[i] = count_cumsum[i - 1] + std::popcount(bits[i - 1]);
            }
        }

        int count0() const { return cnt0; }

        int count1() const { return n - cnt0; }

        // get i-th bit
        bool access(int i) const {
            assert(0 <= i and i < n);
            return bits[i / WSIZE] & (1ULL << (i % WSIZE));
        }

        // count of 0s in [0, i)
        int rank0(int i) const {
            assert(0 <= i and i <= n);
            return i - rank1(i);
        }

        // count of 1s in [0, i)
        int rank1(int i) const {
            assert(0 <= i and i <= n);
            if (i == n) return count1();
            return count_cumsum[i / WSIZE] +
                   std::popcount(bits[i / WSIZE] & ((1ULL << (i % WSIZE)) - 1));
        }

        // get the position of i-th element after stable sort
        int sorted_pos(int i) const { return access(i) ? (rank1(i) + count0()) : rank0(i); }

        template <class OStream> friend OStream &operator<<(OStream &os, const bit_vector &bv) {
            os << "bit_vector[" << bv.n << "]: ";
            for (int i = 0; i < bv.n; ++i) {
                os << (bv.bits[i / WSIZE] & (1ULL << (i % WSIZE)) ? '1' : '0');
            }
            os << " (cnt0: " << bv.cnt0 << ")";
            return os;
        }
    };

    std::vector<bit_vector> bits;

    std::vector<std::pair<Int, Int>> points;
    std::vector<Int> distinct_ys;

    int to_index_x(Int x) const {
        return std::lower_bound(points.cbegin(), points.cend(), std::make_pair(x, Int{}),
                                [](const auto &l, const auto &r) { return l.first < r.first; }) -
               points.cbegin();
    }

    int to_index_y(Int y) const {
        return std::lower_bound(distinct_ys.cbegin(), distinct_ys.cend(), y) - distinct_ys.cbegin();
    }

    bool is_built() const { return !bits.empty(); }

public:
    wavelet_matrix() = default;

    wavelet_matrix(const std::vector<Int> &ys) {
        for (int x = 0; x < (int)ys.size(); ++x) {
            assert(ys[x] >= 0);
            add_point(x, ys[x]);
        }
        build();
    }

    void add_point(Int x, Int y) {
        assert(bits.empty()); // confirm that build() is not called yet
        points.emplace_back(x, y);
        distinct_ys.emplace_back(y);
    }

    void build() {
        std::sort(points.begin(), points.end());
        points.erase(std::unique(points.begin(), points.end()), points.end());

        std::sort(distinct_ys.begin(), distinct_ys.end());
        distinct_ys.erase(std::unique(distinct_ys.begin(), distinct_ys.end()), distinct_ys.end());

        int d = 1;
        while ((1 << d) < (int)distinct_ys.size()) ++d;
        bits.assign(d, bit_vector(N()));

        std::vector<int> a;
        for (auto p : points) a.push_back(to_index_y(p.second));
        auto nxt = a;

        for (int d = D() - 1; d >= 0; --d) {
            for (int i = 0; i < N(); ++i) {
                if ((a[i] >> d) & 1) bits[d].set(i);
            }
            bits[d].build();

            for (int i = 0; i < N(); ++i) nxt[bits[d].sorted_pos(i)] = a[i];

            std::swap(a, nxt);
        }
    }

    int N() const { return points.size(); }

    int D() const { return bits.size(); }

    // get v_i
    int index_access(int i) const {
        assert(0 <= i and i < N());
        assert(is_built());

        int ret = 0;
        for (int d = D() - 1; d >= 0; --d) {
            ret |= (int)bits[d].access(i) << d;
            i = bits[d].sorted_pos(i);
        }
        return ret;
    }

    Int access(int i) const {
        assert(0 <= i and i < N());
        assert(is_built());
        return distinct_ys.at(index_access(i));
    }

    // callback(d, i) means "update d-th segment's i-th element"
    void index_apply(int i, auto callback) const {
        assert(0 <= i and i < N());
        assert(is_built());

        for (int d = D() - 1; d >= 0; --d) {
            i = bits[d].sorted_pos(i);
            callback(d, i);
        }
    }

    // Update weight associated to point (x, y)
    // callback(d, i) means "update d-th segment's i-th element"
    void apply(Int x, Int y, auto callback) const {
        const int i = std::lower_bound(points.cbegin(), points.cend(), std::make_pair(x, y)) -
                      points.cbegin();
        assert(i < N() and points[i] == std::make_pair(x, y));
        index_apply(i, callback);
    }

    void index_prod(int l, int r, int yr, auto callback) const {
        assert(0 <= l and l <= r and r <= N());
        assert(0 <= yr and yr <= (int)distinct_ys.size());
        assert(is_built());

        if (yr & (1 << D())) {
            const int d = D() - 1;
            const int l0 = bits[d].rank0(l), r0 = bits[d].rank0(r);
            callback(d, l0, r0);
            const int l1 = bits[d].rank1(l) + bits[d].count0();
            const int r1 = bits[d].rank1(r) + bits[d].count0();
            callback(d, l1, r1);
            return;
        }

        for (int d = D() - 1; d >= 0; --d) {
            if (l == r) break;
            const int l0 = bits[d].rank0(l), r0 = bits[d].rank0(r);
            if ((yr >> d) & 1) {
                callback(d, l0, r0);
                // l = bits[d].rank1(l) + bits[d].count0();
                l += bits[d].count0() - l0;
                // r = bits[d].rank1(r) + bits[d].count0();
                r += bits[d].count0() - r0;
            } else {
                l = l0, r = r0;
            }
        }
    }

    // Get product of weights associated to elements in [xl, xr) * [-inf, yr)
    // callback(d, l, r) means "use d-th segment's [l, r) elements"
    void prod(Int xl, Int xr, Int yr, auto callback) const {
        index_prod(to_index_x(xl), to_index_x(xr), to_index_y(yr), callback);
    }

    // Get k-th smallest v_i, i in [l, r) (0-indexed, duplicates are counted)]
    int index_kth_smallest(int l, int r, int k) const {
        assert(0 <= l and l <= r and r <= N());
        assert(0 <= k and k < r - l);
        assert(is_built());

        int ret = 0;
        for (int d = D() - 1; d >= 0; --d) {
            const int l0 = bits[d].rank0(l), r0 = bits[d].rank0(r);
            if (k < r0 - l0) {
                l = l0, r = r0;
            } else {
                k -= r0 - l0;
                ret |= 1 << d;
                l = bits[d].rank1(l) + bits[d].count0();
                r = bits[d].rank1(r) + bits[d].count0();
            }
        }

        return ret;
    }

    // Get k-th largest v_i, i in [l, r) (0-indexed, duplicates are counted)
    int index_kth_largest(int l, int r, int k) const {
        assert(0 <= l and l <= r and r <= N());
        assert(0 <= k and k < r - l);
        return index_kth_smallest(l, r, (r - l - 1) - k);
    }

    // count i s.t. i in [l, r) and v_i < upper_bound
    int index_range_freq(int l, int r, int upper_bound) const {
        assert(0 <= l and l <= r and r <= N());
        assert(is_built());
        if (upper_bound <= 0) return 0;
        if (upper_bound >= (int)distinct_ys.size()) return r - l;

        int ret = 0;
        for (int d = D() - 1; d >= 0; --d) {
            const int l0 = bits[d].rank0(l), r0 = bits[d].rank0(r);
            if ((upper_bound >> d) & 1) {
                ret += r0 - l0;
                l = bits[d].rank1(l) + bits[d].count0();
                r = bits[d].rank1(r) + bits[d].count0();
            } else {
                l = l0, r = r0;
            }
        }

        return ret;
    }

    // Get k-th smallest y in [xl, xr) (0-indexed, duplicates are counted)
    std::optional<Int> kth_smallest(Int xl, Int xr, int k) const {
        const int l = to_index_x(xl), r = to_index_x(xr);
        if (k < 0 or k >= r - l) return std::nullopt;
        return distinct_ys.at(index_kth_smallest(l, r, k));
    }

    // Get k-th largest y in [xl, xr) (0-indexed, duplicates are counted)
    std::optional<Int> kth_largest(Int xl, Int xr, int k) const {
        const int l = to_index_x(xl), r = to_index_x(xr);
        if (k < 0 or k >= r - l) return std::nullopt;
        return distinct_ys.at(index_kth_largest(l, r, k));
    }

    // count points in [xl, xr) * [-inf, yr)
    int range_freq(Int xl, Int xr, Int yr) const {
        return index_range_freq(to_index_x(xl), to_index_x(xr), to_index_y(yr));
    }

    // max v_i s.t. i in [l, r), v_i < upper_bound
    std::optional<int> index_prev_value(int l, int r, int upper_bound) const {
        assert(0 <= l and l <= r and r <= N());
        assert(is_built());
        if (upper_bound <= 0) return std::nullopt;

        const int n = index_range_freq(l, r, upper_bound);
        return n == 0 ? std::nullopt : index_kth_smallest(l, r, n - 1);
    }

    // max y s.t. x in [xl, xr), y < yr
    std::optional<Int> prev_value(Int xl, Int xr, Int yr) const {
        const int l = to_index_x(xl), r = to_index_x(xr), ub = to_index_y(yr);
        const auto idx = index_prev_value(l, r, ub);
        return idx ? distinct_ys.at(*idx) : std::nullopt;
    }

    // min v_i s.t. i in [l, r), v_i >= lower_bound
    std::optional<int> index_next_value(int l, int r, int lower_bound) const {
        assert(0 <= l and l <= r and r <= N());
        assert(is_built());
        if (lower_bound >= (int)distinct_ys.size()) return std::nullopt;
        const int n = index_range_freq(l, r, lower_bound);
        return n >= (r - l) ? std::nullopt : index_kth_smallest(l, r, n);
    }

    // min y s.t. x in [xl, xr), y >= yl
    std::optional<Int> next_value(Int l, Int r, Int yl) const {
        const int xl = to_index_x(l), xr = to_index_x(r), yl_idx = to_index_y(yl);
        const auto idx = index_next_value(xl, xr, yl_idx);
        return idx ? distinct_ys.at(*idx) : std::nullopt;
    }
};

#include <atcoder/lazysegtree>

lint op(lint l, lint r) { return max(l, r); }

lint e() { return 0; }
using F = lint;
lint mapping(F f, lint x) { return f + x; }
lint composition(F f, F g) { return f + g; }
lint id() { return 0; }

lint solve(const vector<tuple<int, int, int>> &points, int Ax, int Hy) {
    vector<int> xs, ys;
    for (auto [x, y, w] : points) {
        xs.push_back(x);
        xs.push_back(x + 1);

        xs.push_back(x + Ax - 1);
        xs.push_back(x + Ax);

        xs.push_back(x - Ax);
        xs.push_back(x - Ax + 1);

        ys.push_back(y);
        ys.push_back(y + Hy);
    }

    xs = sort_unique(xs);
    ys = sort_unique(ys);

    // map<int, vector<pint>> events;
    vector<vector<tuple<int, int, int>>> removes(ys.size()), adds(ys.size());
    for (auto [x, y, w] : points) {
        // events[y].emplace_back(x, w);
        // events[y + Hy].emplace_back(x, -w);
        const int lx = arglb(xs, x);
        const int rx = arglb(xs, x + Ax);
        adds.at(arglb(ys, y)).emplace_back(lx, rx, w);
        removes.at(arglb(ys, y + Hy)).emplace_back(lx, rx, -w);
    }

    lint ret = 0;

    atcoder::lazy_segtree<lint, op, e, F, mapping, composition, id> seg(xs.size());
    REP(idx, ys.size()) {
        for (auto [lx, rx, w] : adds.at(idx)) seg.apply(lx, rx, w);

        chmax(ret, seg.all_prod());
        for (auto [lx, rx, w] : removes.at(idx)) seg.apply(lx, rx, w);

        chmax(ret, seg.all_prod());
    }
    return ret;
}

int main() {
    int N, A;
    cin >> N >> A;

    vector<int> xs;
    vector<tuple<int, int, int>> points(N);
    for (auto &[x, y, v] : points) {
        cin >> x >> y >> v;
    }

    lint ret = 0;
    for (int dx : {0, 1}) {
        chmax(ret, solve(points, A + dx, A));
    }

    cout << ret << '\n';
}