#include<iostream>
#include<deque>
#include<vector>
#include<cassert>
using namespace std;
int N,S,H;
int L[2<<17],R[2<<17],Z[2<<17];
long dp[2<<17],ZS[2<<17];
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cin>>N>>S>>H;
	L[0]=R[0]=-H;
	long zs=0;
	for(int i=1;i<=N;i++)
	{
		cin>>L[i]>>R[i]>>Z[i];
		zs+=Z[i];
		ZS[i+1]=ZS[i]+Z[i];
		dp[i]=1e18;
	}
	deque<pair<int,long> >Q;
	int l=0;
	long mx=0;
	for(int i=1;i<=N;i++)
	{
		dp[i]=dp[i-1]+Z[i];
		while(R[l+1]+H<=L[i])l++;
		pair<int,long>t=make_pair(L[i],dp[l]+ZS[i]-ZS[l+1]);
		while(!Q.empty()&&Q.back().second>=t.second)Q.pop_back();
		Q.push_back(t);
		while(!Q.empty()&&Q.front().first+S<R[i])Q.pop_front();
		if(!Q.empty())dp[i]=min(dp[i],Q.front().second);
		mx=max(mx,dp[i]);
	}
	cout<<zs-mx<<endl;
}