#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
istream &operator>>(istream &is, modint &a) { long long v; is >> v; a = v; return is; }
ostream &operator<<(ostream &os, const modint &a) { return os << a.val(); }
istream &operator>>(istream &is, modint998244353 &a) { long long v; is >> v; a = v; return is; }
ostream &operator<<(ostream &os, const modint998244353 &a) { return os << a.val(); }
istream &operator>>(istream &is, modint1000000007 &a) { long long v; is >> v; a = v; return is; }
ostream &operator<<(ostream &os, const modint1000000007 &a) { return os << a.val(); } 

typedef long long ll;
typedef vector<vector<int>> Graph;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define FOR(i,l,r) for (int i = l;i < (int)(r); i++)
#define rep(i,n) for (int i = 0;i < (int)(n); i++)
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define my_sort(x) sort(x.begin(), x.end())
#define my_max(x) *max_element(all(x))
#define my_min(x) *min_element(all(x))
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
const int INF = (1<<30) - 1;
const ll LINF = (1LL<<62) - 1;
const int MOD = 998244353;
const int MOD2 = 1e9+7;
const double PI = acos(-1);
vector<int> di = {1,0,-1,0};
vector<int> dj = {0,1,0,-1};

#ifdef LOCAL
#  include <debug_print.hpp>
#  define debug(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#  define debug(...) (static_cast<void>(0))
#endif

using S = ll;
S op(S a, S b){ return max(a, b); }
S e(){ return -LINF; }
using F = ll;
S mapping(F f, S x){ return f + x; }
F composition(F f, F g){ return f + g; }
F id(){ return 0ll; }


int main(){
    cin.tie(0);
    ios_base::sync_with_stdio(false);
    int N, T, H; cin >> N >> T >> H;
    vector<int> X = {-INF}, Y = {-INF + 1}, Z = {0};
    rep(i, N){
        int x, y, z; cin >> x >> y >> z;
        if(y - x > T) continue;
        X.push_back(x);
        Y.push_back(y);
        Z.push_back(z);
    }
    N = (int)X.size();
    
    lazy_segtree<S, op, e, F, mapping, composition, id> dpx(N);
    segtree<S, op, e> dpy(N + 1);
    dpx.set(0, 0);
    dpy.set(0, 0);

    FOR(i, 1, N){
        debug(i);
        int j = upper_bound(all(Y), X[i] - H) - Y.begin();
        debug(j);
        dpx.set(i, dpy.prod(0, j));
        dpx.apply(0, i + 1, Z[i]);

        int k = lower_bound(all(X), Y[i] - T) - X.begin();
        debug(k);
        dpy.set(i, dpx.prod(k, i + 1));
    }
    cout << dpy.all_prod() << endl;
}