X=334334
N,T=map(int,input().split())
sc=[0]*X*2
for i in range(N):
    L,R,P=map(int,input().split())
    R+=1
    L+=X
    R+=X
    while L<R:
        if L%2==1:
            sc[L]=max(sc[L],P)
            L+=1
        if R%2==1:
            R-=1
            sc[R]=max(sc[R],P)
        L//=2
        R//=2
for i in range(X,X*2):
    now=i
    while now>0:
        sc[i]=max(sc[i],sc[now])
        now//=2
sc=sc[X:]
dp=[0]*X
dp[0]=sc[0]
for i in range(1,T):
    dp[i]=max(dp[i-1],sc[i])
for i in range(T,X):
    dp[i]=max(dp[i-1],dp[i-T]+sc[i])
print(dp[-1])