#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>

#include <atcoder/all>
#define rep(i, a, b) for (ll i = (ll)(a); i < (ll)(b); i++)
using namespace atcoder;
using namespace std;

typedef long long ll;

template <typename T, typename S = vector<T>, typename U = less<T>>
struct priority_queue_ex {
    priority_queue<T, S, U> q, dq;
    void push(T x) { q.push(x); }
    T top() {
        while (dq.size() && q.top() == dq.top()) {
            q.pop();
            dq.pop();
        }
        return q.top();
    }
    T pop() {
        T ret = top();
        q.pop();
        return ret;
    }
    void erase(T x) { dq.push(x); }
    int size() { return q.size() - dq.size(); }
};

template <typename T, typename S>
bool chmax(T &a, S b) {
    if (a < b) {
        a = b;
        return 1;
    }
    return 0;
}

void solve() {
    int n, t;
    cin >> n >> t;
    int mx = 4e5 + 10;
    vector<vector<int>> event(mx);
    rep(i, 0, n) {
        int l, r, p;
        cin >> l >> r >> p;
        event[l].emplace_back(p);
        event[r + 1].emplace_back(-p);
    }
    vector<int> mxp(mx);
    priority_queue_ex<int> pq;
    rep(i, 0, mx) {
        for (auto x : event[i]) {
            if (x >= 0)
                pq.push(x);
            else
                pq.erase(-x);
        }
        if (pq.size() > 0) mxp[i] = pq.top();
    }
    vector<ll> dp(mx);
    rep(i, t, mx) {
        chmax(dp[i], dp[i - t] + mxp[i - t]);
        chmax(dp[i], dp[i - 1]);
    }
    cout << *max_element(dp.begin(), dp.end()) << endl;
}

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