#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using ll = long long;
#define rep(i, s, t) for (ll i = s; i < (ll)(t); i++)

template<typename T>
bool chmin(T &x, T y) { return x > y ? (x = y, true) : false; }
template<typename T>
bool chmax(T &x, T y) { return x < y ? (x = y, true) : false; }

struct io_setup {
	io_setup() {
		ios::sync_with_stdio(false);
		std::cin.tie(nullptr);
		cout << fixed << setprecision(15);
	}
} io_setup;

// template atcoder segtree
using S = ll;
S op(S a, S b){
	return a + b;
}
S e(){
	return 0;
}
using segtree = atcoder::segtree<S,op,e>;

int main(){
	ll n,s,h;
	cin>>n>>s>>h;
	vector<ll> x(n),y(n),z(n);
	rep(i,0,n) cin>>x.at(i)>>y.at(i)>>z.at(i);
	map<ll,vector<ll>> el;
	vector<ll> al={0};
	rep(i,0,n){
		al.push_back(x.at(i));
		al.push_back(y.at(i));
		el[x.at(i)].push_back(y.at(i));
	}
	sort(al.begin(),al.end());
	al.erase(unique(al.begin(),al.end()),al.end());
	int m=al.size();
	auto get_idx=[&](ll a){
		return lower_bound(al.begin(),al.end(),a)-al.begin();
	};
	auto get_uidx=[&](ll a){
		return upper_bound(al.begin(),al.end(),a)-al.begin();
	};
	segtree seg(m);
	rep(i,0,n){
		seg.set(get_idx(y.at(i)),z.at(i));
	}
	vector<ll> dp(m+1,0);
	rep(i,0,m){
		ll nw=al.at(i);
		ll nx=get_idx(nw+s+h);
		chmax(dp.at(nx),dp.at(i)+seg.prod(0,get_uidx(nw+s)));
		if(el.count(nw)){
			for(auto y:el.at(nw)){
				seg.set(get_idx(y),0);
			}
		}
		chmax(dp.at(i+1),dp.at(i));
	}
	cout<<dp.back()<<endl;
}