n,m=map(int,input().split())
l=[0]*5005
r=[0]*5005
v=[0]*5005
for i in range(n):
    l[i],r[i],v[i]=map(int,input().split())
for i in range(n):
    for j in range(n-i):
        if r[j]>r[j+1]:
            l[j],l[j+1]=l[j+1],l[j]
            r[j],r[j+1]=r[j+1],r[j]
            v[j],v[j+1]=v[j+1],v[j]
dp=[0]*100005
i=1
for j in range(m+1):
    if j>0:
        dp[j]=dp[j-1]
    while i<=n and r[i]<=j:
        dp[r[i]]=max(dp[r[i]],dp[l[i]-1]+v[i])
        i+=1
print(dp[m])