#include <iostream>
#include <string>
#include <algorithm>
#include <functional>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <tuple>
#include <cstdio>
#include <cmath>
#include <cassert>
#include <atcoder/modint>
#define rep(i, n) for(i = 0; i < n; i++)
#define int long long
using namespace std;
using namespace atcoder;
using mint = modint998244353;
typedef tuple<int, int, int> T;

int n, t;
vector<T> events; //(time, push(0)/pop(1), val)

signed main() {
	int i, j;

	cin >> n >> t;
	rep(i, n) {
		int l, r, p; cin >> l >> r >> p;
		events.push_back(T(l, 0, p));
		events.push_back(T(r + 1, 1, p));
	}
	sort(events.begin(), events.end());

	const int MAX = 200000;
	multiset<int> st;
	vector<int> maxS(MAX + 1);
	
	j = 0;
	rep(i, MAX + 1) {
		for (; j < events.size() && get<0>(events[j]) == i; j++) {
			int flag = get<1>(events[j]);
			int val = get<2>(events[j]);
			if (flag == 0) {
				st.insert(val);
			}
			else {
				multiset<int>::iterator it = st.find(val);
				st.erase(it);
			}
		}
		if (st.size() == 0) maxS[i] = 0;
		else maxS[i] = *st.rbegin();
	}

	const int INF = 1e+15;
	vector<int> dp(2 * MAX + 1, -INF);
	
	dp[0] = 0;
	rep(i, MAX + 1) {
		dp[i + 1] = max(dp[i + 1], dp[i]);
		dp[i + t] = max(dp[i + t], dp[i] + maxS[i]);
	}

	int ans = -INF;
	rep(i, dp.size()) ans = max(ans, dp[i]);
	
	cout << ans << endl;
	return 0;
}