#if __INCLUDE_LEVEL__ == 0

#include __BASE_FILE__

void Solve() {
  int n;
  int64_t A;
  IN(n, A);
  A *= 2;
  vector<int64_t> X(n), Y(n), V(n);
  for (int i : Rep(0, n)) {
    IN(X[i], Y[i], V[i]);
    X[i] *= 2, Y[i] *= 2;
  }

  vector<int64_t> Ux(n), Uy(n);
  for (int i : Rep(0, n)) {
    Ux[i] = V[i] < 0 ? X[i] - A - 1 : X[i];
    Uy[i] = V[i] < 0 ? Y[i] - A - 1 : Y[i];
  }
  ranges::sort(Ux);
  ranges::sort(Uy);

  vector<vector<tuple<int, int, int64_t>>> events(n + 1);
  for (int i : Rep(0, n)) {
    // [X[i] - A, X[i] + 1)
    int lx = int(ranges::lower_bound(Ux, X[i] - A) - Ux.begin());
    int rx = int(ranges::lower_bound(Ux, X[i] + 1) - Ux.begin());
    int ly = int(ranges::lower_bound(Uy, Y[i] - A) - Uy.begin());
    int ry = int(ranges::lower_bound(Uy, Y[i] + 1) - Uy.begin());
    events[lx].emplace_back(ly, ry, V[i]);
    events[rx].emplace_back(ly, ry, -V[i]);
  }

  int64_t ans = 0;
  vector<int64_t> f(n);
  for (int x : Rep1(0, n)) {
    for (auto [l, r, v] : events[x]) {
      for (int i : Rep(l, r)) {
        f[i] += v;
      }
    }
    if (SetMax(ans, ranges::max(f))) {
    }
  }

  OUT(ans);
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);

  Solve();
}

#elif __INCLUDE_LEVEL__ == 1

#include <bits/stdc++.h>

#include <atcoder/lazysegtree.hpp>

template <class T> concept MyRange = std::ranges::range<T> && !std::convertible_to<T, std::string_view>;
template <class T> concept MyTuple = std::__is_tuple_like<T>::value && !MyRange<T>;

namespace std {

istream& operator>>(istream& is, MyRange auto&& r) {
  for (auto&& e : r) is >> e;
  return is;
}
istream& operator>>(istream& is, MyTuple auto&& t) {
  apply([&](auto&... xs) { (is >> ... >> xs); }, t);
  return is;
}

ostream& operator<<(ostream& os, MyRange auto&& r) {
  auto sep = "";
  for (auto&& e : r) os << exchange(sep, " ") << e;
  return os;
}
ostream& operator<<(ostream& os, MyTuple auto&& t) {
  auto sep = "";
  apply([&](auto&... xs) { ((os << exchange(sep, " ") << xs), ...); }, t);
  return os;
}

}  // namespace std

using namespace std;

#define LAMBDA2(x, y, ...) ([&](auto&& x, auto&& y) -> decltype(auto) { return __VA_ARGS__; })
#define Rep(...) [](int l, int r) { return views::iota(min(l, r), r); }(__VA_ARGS__)
#define Rep1(...) [](int l, int r) { return Rep(l, r + 1); }(__VA_ARGS__)
#define SetMax(...) LAMBDA2(x, y, x < y && (x = y, 1))(__VA_ARGS__)
#define IN(...) (cin >> forward_as_tuple(__VA_ARGS__))
#define OUT(...) (cout << forward_as_tuple(__VA_ARGS__) << '\n')

#endif  // __INCLUDE_LEVEL__ == 1