#ifndef _GLIBCXX_NO_ASSERT
#include <cassert>
#endif
#include <cctype>
#include <cerrno>
#include <cfloat>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#if __cplusplus >= 201103L
#include <ccomplex>
#include <cfenv>
#include <cinttypes>
#include <cstdbool>
#include <cstdint>
#include <ctgmath>
#include <cwchar>
#include <cwctype>
#endif
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#if __cplusplus >= 201103L
#include <array>
#include <atomic>
#include <chrono>
#include <condition_variable>
#include <forward_list>
#include <future>
#include <initializer_list>
#include <mutex>
#include <random>
#include <ratio>
#include <regex>
#include <scoped_allocator>
#include <system_error>
#include <thread>
#include <tuple>
#include <typeindex>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#endif
using namespace std;
using namespace std;
using i64 = int64_t;
using vi = vector<i64>;
using vvi = vector<vi>;
using ii = pair<int, i64>;

map<i64, i64> compX, compY, extX, extY;
map<ii, i64> point;
vvi board, boardp;

// all inclusive
i64 pointsum(int i0, int i1, int j0, int j1) {
    i0++;
    i1++;
    j0++;
    j1++;
    return board[i1][j1] - board[i1][j0 - 1] - board[i0 - 1][j1] + board[i0 - 1][j0 - 1];
}

i64 pointnum(int i0, int i1, int j0, int j1) {
    i0++;
    i1++;
    j0++;
    j1++;
    return boardp[i1][j1] - boardp[i1][j0 - 1] - boardp[i0 - 1][j1] + boardp[i0 - 1][j0 - 1];
}

int main() {
    int n, b;
    cin >> n >> b;
    
    for (int i = 0; i < n; i++) {
        i64 x, y, p;
        cin >> x >> y >> p;
        
        compX[x] = compY[y] = 0;
        point[ii(x, y)] = p;
    }
    
    int k = 0;
    for (auto& p: compX) {
        p.second = k++;
        extX[p.second] = p.first;
    }
    k = 0;
    for (auto& p: compY) {
        p.second = k++;
        extY[p.second] = p.first;
    }
    
    int X = compX.size(), Y = compY.size();
    board = vvi(X + 1, vi(Y + 1));
    boardp = vvi(X + 1, vi(Y + 1));
    for (int i = 0; i < X; i++) {
        for (int j = 0; j < Y; j++) {
            board[i + 1][j + 1] = point[ii(extX[i], extY[j])];
            boardp[i + 1][j + 1] = point[ii(extX[i], extY[j])] > 0;
        }
    }
    
    for (int i = 0; i <= X; i++) {
        for (int j = 0; j < Y; j++) {
            board[i][j + 1] += board[i][j];
            boardp[i][j + 1] += boardp[i][j];
        }
    }
    
    for (int j = 0; j <= Y; j++) {
        for (int i = 0; i < X; i++) {
            board[i + 1][j] += board[i][j];
            boardp[i + 1][j] += boardp[i][j];
        }
    }
    
    i64 ans = 0;
    for (int i = 0; i < X; i++) {
        for (int j = i; j < X; j++) {
            i64 sum = 0;
            int l = 0, r = 0;
            while (1) {
                if (sum <= b) {
                    sum += pointsum(i, j, r, r);
                    if (sum <= b) {
                        ans = max(ans, pointnum(i, j, l, r));
                    }
                    r++;
                    if (r == Y) {
                        break;
                    }
                } if (sum > b) {
                    sum -= pointsum(i, j, l, l);
                    l++;
                }
            }
        }
    }
    
    cout << ans << endl;
}