import sys
input = sys.stdin.readline
N,T = map(int,input().split())
LRP = [tuple(map(int,input().split())) for _ in range(N)]
LRP.sort(key=lambda x:x[1])

from atcoder.segtree import SegTree
INF = 10**18
MAXT = 4*10**5 + 5
segt = SegTree(max, -INF, MAXT)
B = 10**6

segt.set(0,MAXT)

for l,r,p in LRP:
    l += T
    r += T
    v = segt.prod(0,r-T+1)
    x,m = divmod(v,B)
    t = MAXT - m
    assert t+T <= r
    nv = (x+p)*B + (MAXT - (t+T))
    segt.set(t+T, max(segt.get(t+T), nv))

print(segt.all_prod() // B)