#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using vll = vector<ll>;
using pll = pair<ll,ll>;
#define rep(i,n) for(int i=0;i<(n);i++)
#define rrep(i,n) for(int i=(n)-1;0<=i;i--)
#define REP(i,n) for(int i=1;i<=n;i++)
#define all(a) a.begin(),a.end()
#define sort(a) sort(all(a))
#define rev(a) reverse(all(a))
char el='\n';
void YN(bool f){cout<<(f?"Yes":"No")<<"\n";}
template<typename T> bool chmin(T& x,T y){if(x>y){x=y;return true;}return false;}
template<typename T> bool chmax(T& x,T y){if(x<y){x=y;return true;}return false;}
template <typename T> istream &operator>>(istream &is, vector<T> &v){ for(T &in : v) is >> in; return is;}
template <typename T> ostream &operator<<(ostream &os, vector<T> &v){ rep(i,v.size()) os << v[i] << (i+1==v.size()?"":" "); return os;}

template<class T,class E,T op_id,E ef_id,T(*op)(T,T),void(*ch)(T&,E),void(*sy)(E&,E)>
struct LazySegmentTree{
    private:
    int n=1;
    vector<T> k;
    vector<E> lazy;
    vector<bool> flag;
    public:
    void eval(int i,int l,int r){
        if(flag[i]){
            ch(k[i],lazy[i]);
            if(l+1<r){
                sy(lazy[2*i],lazy[i]);
                sy(lazy[2*i+1],lazy[i]);
                flag[2*i]=flag[2*i+1]=true;
            }
            flag[i]=false;
            lazy[i]=ef_id;
        }
    }
    void update(int a,int b,int i,int l,int r,E x){
        eval(i,l,r);
        if(r<=a||b<=l) return;
        if(a<=l&&r<=b){
            sy(lazy[i],x);
            flag[i]=true;
            eval(i,l,r);
        }
        else{
            update(a,b,i*2,l,(l+r)/2,x);
            update(a,b,i*2+1,(l+r)/2,r,x);
            k[i]=op(k[i*2],k[i*2+1]);
        }
    }
    void update(int a,int b,E x){
        update(a,b,1,0,n,x);
    }
    T query(int a,int b,int i,int l,int r){
        eval(i,l,r);
        if(r<=a||b<=l) return op_id;
        if(a<=l&&r<=b) return k[i];
        T v1=query(a,b,i*2,l,(l+r)/2);
        T v2=query(a,b,i*2+1,(l+r)/2,r);
        return op(v1,v2);
    }
    T query(int a, int b) {
        return query(a,b,1,0,n);
    }
    LazySegmentTree(vector<T> a){
        int m=a.size();
        while(n<m) n*=2;
        k=vector<T>(n*2,op_id);
        lazy=vector<E>(n*2,ef_id);
        flag=vector<bool>(n*2,false);
        rep(i,m) k[n+i]=a[i];
        for(int i=n-1;0<i;i--) k[i]=op(k[i*2],k[i*2+1]);
    }
};

ll mx(ll x,ll y){ return max(x,y); }
void mx(ll& x,ll y){ x = max(x,y); }

int main(){
    int n, t; cin >> n >> t;
    vll l(n), r(n), p(n);
    rep(i,n) cin >> l[i] >> r[i] >> p[i];

    LazySegmentTree<ll,ll,0,0,mx,mx,mx> sg(vll(202020));
    rep(i,n) sg.update(l[i], r[i]+1, p[i]);

    vll dp(202020);
    rep(i,202020){
        if(i) chmax(dp[i], dp[i-1]);
        if(i+t<202020) chmax(dp[i+t], dp[i]+sg.query(i,i+1));
    }

    cout << dp[202010] << el;

}