#include<bits/stdc++.h>
using namespace std;
#define int long long
signed main() {
	int n,s,t;
	cin >> n >> s >> t;
	vector<int> x,y,z;
	for(int i = 0; i < n; i++) {
		int a,b,c;
		cin >> a >> b >> c;
		if(b-a > s) continue;
		x.push_back(a);
		y.push_back(b);
		z.push_back(c);
	}
	n = x.size();
	vector<int> e(n,0);
	for(int i = 0; i < n; i++) {
		int g = lower_bound(y.begin(),y.end(),x[i]-t)-y.begin();
		e[i] = g;
	}
	vector<int> dp(n+1,0);
	vector<int> dp2(n+1,0);
	for(int i = 0; i < n; i++) {
		dp[i+1] = dp2[e[i]]+z[i];
		dp2[i+1] = max(dp2[i],dp[i+1]);
	}
	cout << dp2[n] << endl;
}