#include <bits/stdc++.h>
using namespace std;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
typedef long long ll;
typedef long double ld;
#define INF 2001001001
#define MOD 1000000007
int N;
int L[1000001];
vector<pair<int,int>>adj[1000001];
bool vis[1000001];
ll ans,mx,mx2;
ll dis[1000001];
int prop,parStore;
pair<int,int>back; ll backCost;
int bad;
void dfs(int node, int par){
//cout<<"dfs: "<<node<<' '<<par<<endl;
vis[node]=true;
vector<ll>v;
for (auto p:adj[node]){
if (vis[p.first]){
if (p.first!=par && backCost==-1){
back={p.first,node};
prop=node;
parStore=par;
backCost=p.second;
}
}
else{
dfs(p.first,node);
v.push_back(dis[p.first]+p.second);
}
}
if (node==prop && par!=back.first)
prop=par;
if ((int)v.size()==0) return;
sort(v.begin(),v.end());
dis[node]=v.back();
if (v.size()==1)
mx=max(mx,v[0]);
else
mx=max(mx,v.back()+v[(int)v.size()-2]);
}
void dfs2(int node, int par, ll depth){
mx2=max(mx2,depth);
for (auto p:adj[node]){
if (p.first==par || p.first==bad)
continue;
dfs2(p.first,node,depth+p.second);
}
}
map<pair<int,int>,int>mp;
int main()
{
//ios_base::sync_with_stdio(0);cin.tie(0);
//freopen (".in","r",stdin);
//freopen (".out","w",stdout);
scanf("%d",&N);
for (int i=1;i<=N;i++){
int Y;
scanf("%d%d",&Y,&L[i]);
int x=i,y=Y;
if (x>y) swap(x,y);
mp[{x,y}]=max(mp[{x,y}],L[i]);
}
for (auto it:mp){
adj[it.first.first].push_back({it.first.second,it.second});
adj[it.first.second].push_back({it.first.first,it.second});
}
for (int i=1;i<=N;i++)
if (!vis[i]){
//cout<<"COMPONENT: "<<i<<endl;
mx=0;
backCost=-1;
dfs(i,i);
if (backCost==-1){
ans+=mx;
continue;
}
//cout<<"MX: "<<mx<<endl;
mx2=0; bad=back.second;
//cout<<"dfs2: "<<back.first<<' '<<prop<<endl;
dfs2(back.first,prop,0);
ll temp=mx2;
mx2=0; bad=back.first;
//cout<<"dfs2: "<<back.second<<' '<<parStore<<endl;
dfs2(back.second,parStore,0);
//cout<<"MX2: "<<temp<<' '<<mx2<<endl;
mx=max(mx,mx2+temp+backCost);
ans+=mx;
}
cout<<ans<<endl;
return 0;
}
