//Author: Kevin
#include<bits/stdc++.h>
//#pragma GCC optimize("O2")
using namespace std;
#define ll long long
#define ull unsigned ll
#define pb emplace_back
#define mp make_pair
#define ALL(x) (x).begin(),(x).end()
#define rALL(x) (x).rbegin(),(x).rend()
#define srt(x) sort(ALL(x))
#define rev(x) greverse(ALL(x))
#define rsrt(x) sort(rALL(x))
#define sz(x) (int)(x.size())
#define inf 0x3f3f3f3f
#define pii pair<int,int>
#define lb(v,x) (int)(lower_bound(ALL(v),x)-v.begin())
#define ub(v,x) (int)(upper_bound(ALL(v),x)-v.begin())
#define uni(v) v.resize(unique(ALL(v))-v.begin())
#define longer __int128_t
void die(string S){puts(S.c_str());exit(0);}
int n;
int l[300300],r[300300];
ll w[300300];
ll dp[500500];
int lst[500500];
int choose[500500];
ll dist[500500];
int inque[500500];
vector<pair<int,ll>> G[500500];
int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	cin>>n;
	for(int i=1;i<=n;i++)
		cin>>l[i]>>r[i]>>w[i];
	vector<pii> vec;
	for(int i=1;i<=n;i++)
		vec.pb(l[i],i);
	srt(vec);
	int p=0;
	memset(dp,-inf,sizeof(dp));
	dp[0]=0;
	for(int i=0;i<=500000;i++)
	{
		if(dp[i]>dp[i+1])
		{
			dp[i+1]=dp[i];
			lst[i+1]=-1;
		}
		while(p<sz(vec)&&vec[p].first==i+1)
		{
			if(dp[i]+w[vec[p].second]>dp[r[vec[p].second]])
			{
				dp[r[vec[p].second]]=dp[i]+w[vec[p].second];
				lst[r[vec[p].second]]=vec[p].second;
			}
			p++;
		}
	}
	ll ans=dp[500000];
	int cur=500000;
	while(cur)
	{
		if(lst[cur]==-1)
		{
			G[cur].pb(cur-1,0);
			cur--;
		}
		else
		{
			choose[lst[cur]]=1;
			cur=l[lst[cur]]-1;
		}
	}
	memset(dist,-inf,sizeof(dist));
	priority_queue<pair<ll,int>> pq;
	pq.emplace(0,0);
	dist[0]=0;
	for(int i=1;i<=500000;i++)
		G[i-1].pb(i,0);
	for(int i=1;i<=n;i++)
		if(!choose[i])
			G[l[i]-1].pb(r[i],w[i]);
		else
			G[r[i]].pb(l[i]-1,-w[i]);
	while(!pq.empty())
	{
		ll d=pq.top().first;
		int x=pq.top().second;
		pq.pop();
		if(dist[x]!=d) continue;
		for(auto pr:G[x])
		{
			ll nd=pr.second+dp[x]-dp[pr.first]+dist[x];
			if(nd>dist[pr.first])
			{
				dist[pr.first]=nd;
				pq.emplace(nd,pr.first);
			}
		}
	}
	cout<<ans*2+dist[500000]<<endl;
	return 0;
}