#include <bits/stdc++.h>
using namespace std;

constexpr int SIZE = 2 << 17;
long long dp[SIZE];
vector<pair<int, int>> PR[SIZE];
priority_queue<pair<int, int>> pq;
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int N, T;
    cin >> N >> T;
    while (N--) {
        int l, r, p;
        cin >> l >> r >> p;
        PR[l + 1].emplace_back(p, r + 1);
    }

    pq.push({0, SIZE});
    for (int i = 1; i < SIZE; i++) {
        for (auto [p, r] : PR[i]) {
            pq.push({p, r});
        }
        while (pq.top().second < i) pq.pop();
        dp[i] = max(dp[i - 1], dp[max(0, i - T)] + pq.top().first);
    }
    cout << dp[SIZE - 1] << endl;
}