#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vector<int>;
using vl = vector<ll>;
#define ov4(a, b, c, d, name, ...) name
#define rep3(i, a, b, c) for(ll i = (a); i < (b); i += (c))
#define rep2(i, a, b) rep3(i, a, b, 1)
#define rep1(i, n) rep2(i, 0, n)
#define rep0(n) rep1(aaaaa, n)
#define rep(...) ov4(__VA_ARGS__, rep3, rep2, rep1, rep0)(__VA_ARGS__)
#define per(i, a, b) for(ll i = (a)-1; i >= (b); i--)
#define fore(e, v) for(auto&& e : v)
#define all(a) begin(a), end(a)
#define si(a) (int)(size(a))
#define lb(v, x) (lower_bound(all(v), x) - begin(v))
#define eb emplace_back

template<typename T, typename S> bool chmin(T& a, const S& b) { return a > b ? a = b, 1 : 0; }
template<typename T, typename S> bool chmax(T& a, const S& b) { return a < b ? a = b, 1 : 0; }

const int INF = 1e9 + 100;
const ll INFL = 3e18 + 100;

#define i128 __int128_t
constexpr int mod = 998244353;
struct mint {
   int x;
   mint(ll x_ = 0) : x(x_ % mod) {
      if(x < 0) x += mod;
   }
   mint operator-() {
      auto res = *this;
      res.x = (x ? mod - x : 0);
      return res;
   }
   mint& operator+=(mint r) {
      if((x += r.x) >= mod) x -= mod;
      return *this;
   }
   mint& operator-=(mint r) {
      if((x -= r.x) < 0) x += mod;
      return *this;
   }
   mint& operator*=(mint r) {
      x = 1LL * x * r.x % mod;
      return *this;
   }
   mint& operator/=(mint r) { return *this *= r.inv(); }
   friend mint operator+(mint a, mint b) { return a += b; }
   friend mint operator-(mint a, mint b) { return a -= b; }
   friend mint operator*(mint a, mint b) { return a *= b; }
   friend mint operator/(mint a, mint b) { return a /= b; }
   mint inv() const { return pow(mod - 2); }
   mint pow(ll b) const {
      mint a = *this, c = 1;
      while(b) {
         if(b & 1) c *= a;
         a *= a;
         b >>= 1;
      }
      return c;
   }
};
/*
aaaaa
aaaaa
aaaaa
aaaaa
aaaaa
*/
using vm = vector<mint>;
int main() { 
    cin.tie(0)->sync_with_stdio(0); 

    ll n,w;
    cin >> n >> w;
    vector<pll> a;
    ll m = 400000+10;
    vl v(m,0);
    multiset<ll> s;
    vector<tuple<ll,ll,ll>> event;
    rep(i,n){
        ll l,r,p;
        cin >> l >> r >> p;
        a.emplace_back(l,r);
        chmax(v[l],p);
        event.emplace_back(l,0,p);
        event.emplace_back(r,2,p);

    }
    rep(i,m){
        event.emplace_back(i,1,-1);
    }

    vl dp(m,-1LL<<60);
    dp[0] = 0;

    sort(all(event));
    s.emplace(0);

    for(auto [l,t,x]:event){
        if(t == 0){
            s.emplace(x);
        }
        if(t == 1){
            ll i = l;

            if(i+w < si(dp))chmax(dp[i+w],dp[i] + (*prev(s.end())));
            if(i+1 < si(dp))chmax(dp[i+1],dp[i]);
        }
        if(t == 2){
            s.erase(s.find(x));
        }
    }
    
    
    cout << dp.back() << endl;
    

    
}