from collections import defaultdict
from heapq import heappush, heappop
from typing import Iterable

class DeletableHeapq:
    def __init__(self, items: Iterable=[], reverse=False) -> None:
        self._heap = []
        self._sum = 0
        self._len = len(list(items))
        self._count = defaultdict(int)
        self._sign = -1 if reverse else 1
        for x in items:
            self.push(x)

    def __len__(self) -> int:
        return self._len

    def __contains__(self, x: int) -> bool:
        return self._count.get(x, 0) > 0

    def push(self, x: int) -> None:
        self._sum += x
        self._len += 1
        self._count[x] += 1
        heappush(self._heap, x * self._sign)
        
    def pop(self) -> int:
        assert self._len > 0
        self._update()
        x = heappop(self._heap) * self._sign
        self._sum -= x
        self._len -= 1
        self._count[x] -= 1
        return x
    
    def top(self) -> int:
        assert len(self) > 0
        self._update()
        return self._heap[0] * self._sign

    def remove(self, x: int) -> None:
        assert x in self
        self._sum -= x
        self._len -= 1
        self._count[x] -= 1
    
    def _update(self) -> None:
        while self._heap:
            x = self._heap[0] * self._sign
            if x in self:
                return
            heappop(self._heap)
    
    @property
    def sum(self) -> int:
        return self._sum
    
    def count(self, x: int) -> int:
        return self._count.get(x, 0)

N, T = map(int, input().split())
SIZE = 2 << 17
LP = [[] for _ in range(SIZE)]
RP = [[] for _ in range(SIZE)]
for _ in range(N):
    l, r, p = map(int, input().split())
    LP[l].append(p)
    RP[r].append(p)

dp = [0] * SIZE
dhq = DeletableHeapq([0], reverse=True)
for i, (lp, rp) in enumerate(zip(LP, RP)):
    for p in lp:
        dhq.push(p)
    dp[i] = max(dp[i - 1], dp[i - T] + dhq.top())
    for p in rp:
        dhq.remove(p)
print(dp[-1])