#include <bits/stdc++.h>
using namespace std;
using std::cout;
using std::cin;
using std::endl;
using ll=long long;
using ld=long double;
const ll ILL=2167167167167167167;
const int INF=2100000000;
const int mod=998244353;
#define rep(i,a,b) for (int i=(int)(a);i<(int)(b);i++)
#define all(p) p.begin(),p.end()
template<class T> using _pq = priority_queue<T, vector<T>, greater<T>>;
template<class T> ll LB(vector<T> &v,T a){return lower_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> ll UB(vector<T> &v,T a){return upper_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> bool chmin(T &a,T b){if(a>b){a=b;return 1;}else return 0;}
template<class T> bool chmax(T &a,T b){if(a<b){a=b;return 1;}else return 0;}
template<class T> void So(vector<T> &v) {sort(v.begin(),v.end());}
template<class T> void Sore(vector<T> &v) {sort(v.begin(),v.end(),[](T x,T y){return x>y;});}
bool yneos(bool a,bool upp=0){if(a){cout<<(upp?"YES\n":"Yes\n");}else{cout<<(upp?"NO\n":"No\n");}return a;}
template<class T> void vec_out(vector<T> &p,int ty=0){
if(ty==2){cout<<'{';for(int i=0;i<(int)p.size();i++){if(i){cout<<",";}cout<<'"'<<p[i]<<'"';}cout<<"}\n";}
else{if(ty==1){cout<<p.size()<<"\n";}for(int i=0;i<(int)(p.size());i++){if(i) cout<<" ";cout<<p[i];}cout<<"\n";}}
template<class T> T vec_min(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmin(ans,x);return ans;}
template<class T> T vec_max(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmax(ans,x);return ans;}
template<class T> T vec_sum(vector<T> &a){T ans=T(0);for(auto &x:a) ans+=x;return ans;}
int pop_count(long long a){int res=0;while(a){res+=(a&1),a>>=1;}return res;}
template<class T> bool inside(T l,T x,T r){return l<=x&&x<r;}

#include <atcoder/lazysegtree>


using lazy_S = ll;

using lazy_F = ll;

lazy_S lazy_op(lazy_S l, lazy_S r) {
    return max(l, r);
}

lazy_S lazy_e() { return -ILL; }

lazy_S mapping(lazy_F l, lazy_S r) {
    return l + r;
}

//l(r(x))
lazy_F composition(lazy_F l, lazy_F r) {
    return l + r;
}

lazy_F lazy_id(){return 0;}

#define lazy_calc lazy_S,lazy_op,lazy_e,lazy_F,mapping,composition,lazy_id


void solve();
// CYAN / FREDERIC
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    
    int t = 1;
    // cin >> t;
    rep(i, 0, t) solve();
}

void solve(){
    ll N, S, H;
    cin >> N >> S >> H;
    vector<ll> X, Y, Z;
    set<ll> s;
    rep(i, 0, N){
        ll x, y, z;
        cin >> x >> y >> z;
        if (y - x > S) continue;
        X.push_back(x);
        Y.push_back(y);
        Z.push_back(z);
        s.insert(x);
        s.insert(y);
    }
    N = X.size();
    if (N == 0){
        cout << "0\n";
        return;
    }
    map<ll, int> m;
    vector<ll> v;
    int len = s.size();
    for (auto x : s) m[x] = v.size(), v.push_back(x);
    vector<int> order(N);
    rep(i, 0, N) order[i] = i;
    sort(all(order), [&](int l, int r){
        return Y[l] < Y[r];
    });
    vector<int> inv(N);
    rep(i, 0, N) inv[order[i]] = i;
    vector<vector<int>> G(len);
    rep(i, 0, N){
        G[m[X[i]]].push_back(i);
    }
    v.push_back(ILL);
    vector<ll> dp(len + 1);
    atcoder::lazy_segtree<lazy_calc> seg(len);
    int j = len;
    for (int i = len - 1; i >= 0; i--){
        for (auto x : G[i]){
            seg.apply(m[Y[x]], len, Z[x]);
        }
        while (v[j - 1] > S + v[i]){
            j--;
        }
        /*cout << i << " "<< j << " "<< v[i] << endl;
        rep(i, 0, len) cout << max((ll)(-1), seg.get(i)) << " ";
        cout << endl;
        */
        dp[i] = seg.prod(i, j);
        chmax(dp[i], dp[i + 1]);
        seg.set(i, dp[LB(v, v[i] + H)]);
    }
    cout << dp[0] << "\n";
}