#ifdef ONLINE_JUDGE
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#endif
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
#define rep(i, n) for (ll i = 0; i < (ll)(n); i++)
#define rrep(i,start,end) for (ll i = start;i >= (ll)(end);i--)
#define repn(i,end) for(ll i = 0; i <= (ll)(end); i++)
#define reps(i,start,end) for(ll i = start; i < (ll)(end); i++)
#define repsn(i,start,end) for(ll i = start; i <= (ll)(end); i++)
#define each(p,a) for(auto &p:a)
typedef vector<ll> vll;
typedef vector<pair<ll ,ll>> vpll;
typedef vector<vector<pair<ll ,ll>>> vvpll;
typedef vector<vector<ll>> vvll;
typedef vector<vector<vector<ll>>> vvvll;
typedef set<ll> sll;
typedef map<ll , ll> mpll;
typedef pair<ll ,ll> pll;
typedef tuple<ll , ll , ll> tpl3;
typedef tuple<ll , ll , ll , ll> tpl4;
typedef tuple<ll , ll , ll , ll , ll> tpl5;
typedef tuple<ll , ll , ll , ll , ll , ll> tpl6;
#define LL(...) ll __VA_ARGS__; input(__VA_ARGS__)
#define LD(...) ld __VA_ARGS__; input(__VA_ARGS__)
#define Str(...) string __VA_ARGS__; input(__VA_ARGS__)
#define Ch(...) char __VA_ARGS__; input(__VA_ARGS__)
#define all(a)  (a).begin(),(a).end()
#define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() );
#define sz(x) (ll)x.size()
// << std::fixed << std::setprecision(10)
const ll INF = 1LL << 60;
const ld EPS = 1e-9;
 
ll lceil(ll a,ll b){if(a%b==0){return a/b;}if(a>=0){return (a/b)+1;}else{return -((-a)/b);}}
ll lfloor(ll a,ll b){if(a%b==0){return a/b;}if(a>=0){return (a/b);}else{return -((-a)/b)-1;}}
inline ll positive_mod(ll a,ll m){return (a % m + m)%m;}
inline ll popcnt(ull a){ return __builtin_popcountll(a);}
//0indexed
inline ll topbit(ll a){assert(a != 0);return 63 - __builtin_clzll(a);}
inline ll smlbit(ll a){assert(a != 0);return __builtin_ctzll(a);}
template<class T> bool chmin(T& a, T b){if(a > b){a = b;return true;}return false;}
template<class T> bool chmax(T& a, T b){if(a < b){a = b;return true;}return false;}
template<typename T> std::istream &operator>>(std::istream&is,std::vector<T>&v){for(T &in:v){is>>in;}return is;}
template<typename T> std::ostream &operator<<(std::ostream&os,const std::vector<T>&v){for(auto it=std::begin(v);it!=std::end(v);){os<<*it<<((++it)!=std::end(v)?" ":"");}return os;}
template<typename T1, typename T2>std::ostream &operator<< (std::ostream &os, std::pair<T1,T2> p){os << "{" << p.first << "," << p.second << "}";return os;}
template<class... T>void input(T&... a){(cin >> ... >> a);}
void print(){cout << endl;}
template<class T, class... Ts>void print(const T& a, const Ts&... b){cout << a;((cout << ' ' << b), ...);cout << endl;}
template<class T> void pspace(const T& a){ cout << a << ' ';}
void perr(){cerr << endl;}
template<class T, class... Ts>void perr(const T& a, const Ts&... b){cerr << a;((cerr << ' ' << b), ...);cerr << endl;}
void yes(bool i = true){ return print(i?"yes":"no"); }
void Yes(bool i = true){ return print(i?"Yes":"No"); }
void YES(bool i = true){ return print(i?"YES":"NO"); }
template <class T> vector<T> &operator++(vector<T> &v) {for(auto &e : v) e++;return v;}
template <class T> vector<T> operator++(vector<T> &v, signed) {auto res = v;for(auto &e : v) e++;return res;}
template <class T> vector<T> &operator--(vector<T> &v) {for(auto &e : v) e--;return v;}
template <class T> vector<T> operator--(vector<T> &v, signed) {auto res = v;for(auto &e : v) e--;return res;}
//grid探索用
vector<ll> _ta = {0,0,1,-1,1,1,-1,-1};
vector<ll> _yo = {1,-1,0,0,1,-1,1,-1};
bool isin(ll now_i,ll now_j,ll h,ll w){return (0<=now_i && now_i < h && 0 <= now_j && now_j < w);}
  
ll lpow(ll x,ll n){ll ans = 1;while(n >0){if(n & 1)ans *= x;x *= x;n >>= 1;}return ans;}
ll Modlpow(ll x,ll n,ll m){ll ans = 1;ll a = x%m;while(n >0){if(n & 1){ans *= a;ans%= m;}a *= a;a %= m;n >>= 1;}return ans;} 
const ll MOD9 = 998244353LL;
const ll MOD10 = 1000000007LL;
 
using mint = modint998244353;

//双対セグ木
//verify https://onlinejudge.u-aizu.ac.jp/solutions/problem/DSL_2_D/review/8951597/T21140031/C++17
template<class M>
struct DualSegmentTree{
  using FM = function<M(M,M)>;
  ll siz ;
  FM fm;
  const M em;//Mの単位元
  vector<M> lazy;
  ll height;
  
  DualSegmentTree(ll n,FM _fm,M _em):fm(_fm),em(_em)
  {
    ll i = 0;
    while((1 << i) < n){
      i++;
    }
    lazy.resize(1 << (i+1),_em);
    siz = 1 << i;
    height = i;
  }

  void all_apply(ll p,M m){
    lazy[p] = fm(lazy[p],m);
  }

  void push(ll p){
    if(lazy[p] == em)return ;
    all_apply(2 * p,lazy[p]);
    all_apply(2 * p+1,lazy[p]);
    lazy[p] = em;
  }

  M get(ll p){
    p+= siz;
    for(ll i = height;i >= 1;i--){
      push(p >> i);
    }
    return lazy[p];
  }

  M query(ll pos){
    return get(pos);
  }

  void update(ll l,ll r, M m){
    if(l == r)return ;
    l+= siz;
    r+= siz;

    for(ll i = height;i>= 1;i--){
      if(((l>> i) << i) != l)push(l >> i);
      if(((r>> i) << i) != r)push((r-1) >>i);
    }
    
   ll tmpl = l,tmpr = r;
    while(l < r){
      if(l & 1) all_apply(l++,m);
      if(r & 1) all_apply(--r,m);
      l>>= 1;
      r>>= 1;
    }
    l = tmpl;
    r = tmpr;
  }
  M operator[](ll pos){
    return get(pos);
  }
 
};
int main(){
  ios::sync_with_stdio(false);cin.tie(nullptr);
  LL(n,t);
  ll lim = 2*lpow(10,5)+10;
  DualSegmentTree<ll> seg(lim,[](ll u,ll v){return max(u,v);},0);
  rep(i,n){
    LL(l,r,p);
    seg.update(l,r+1,p);
  }
  vector<ll> dp(lim+1,-INF);
  dp[0] = 0;
  rep(i,lim){
    chmax(dp[i+1],dp[i]);
    if(seg.get(i) > 0){
      chmax(dp[min(i+t,lim)],dp[i]+seg.get(i));
    }
  }
  cout << dp[lim] << endl;
}