#include<iostream>
#include<stack>
#include<map>
#include<vector>
#include<string>
#include<cassert>
#include<unordered_map>
#include <queue>
#include <cstdint>
#include<cstring>
#include<limits.h>
#include<cmath>
#include<set>
#include<algorithm>
#include <iomanip>
#include<numeric>
#include<bitset>
using namespace std;
#define ll long long
#define f first
#define s second
#define pii pair<int,int>
#define ppii pair<int,pii>
#define vi vector<int>
#define pb push_back
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define F(n) for(int i=0;i<n;i++)
#define lb lower_bound
#define ub upper_bound
#define fastio ios::sync_with_stdio(false);cin.tie(NULL);
#pragma GCC optimize ("03,unroll-lopps")
//#define int long long
using namespace std;
const int mod=1e9+7,mxn=1e6+5,inf=1e9,minf=-1e9,lg=25;
int n,m,k,x,y,z=0;
vector<pair<int,ll>>adj[mxn+10];
int have=0,pointer=0;
int up[mxn+10],dup[mxn+10];
pii cycle[mxn+10];
ll dp1[mxn+10],mx,suf[mxn+10];
//8^106
bitset<mxn+10>on,vis;
ll ans=0,pref=0,prefmx=0;
queue<pii>q;
map<pii,int>mp;
ll m1=0,m2=0;
void dfs(int cur,int p){//fake dfs
q.push({cur,-1});
while(!q.empty()){
cur=q.front().f,p=q.front().s;
q.pop();
if(vis[cur])continue;
vis[cur]=1;
for(auto i:adj[cur]){
if(i.f==p)continue;
if(vis[i.f]&&!have){
x=cur,y=i.f,z=i.s;
have++;
}
if(!vis[i.f])q.push({i.f,cur});
}
}
}
void dfs1(int cur,int p){//dont take edge x,y
q.push({cur,-1});
while(!q.empty()){
cur=q.front().f,p=q.front().s;
q.pop();
for(auto i:adj[cur]){
if(i.f==p)continue;
if(cur==x&&i.f==y)continue;
if(cur==y&&i.f==x)continue;
up[i.f]=cur;
dup[i.f]=i.s;
dp1[i.f]=dp1[cur]+1;
q.push({i.f,cur});
}
cycle[pointer++]={dp1[cur],cur};
dp1[cur]=0;
}
}
//find diameter
int32_t main(){
fastio
cin>>n;
for(int i=1;i<=n;i++){
int a,b;cin>>a>>b;
adj[a].pb({i,b});
adj[i].pb({a,b});
/*
pii x={min(a,i),max(a,i)};
if(mp.find(x)==mp.end())mp[x]=b;
else mp[x]=max(mp[x],b);*/
}
/*
for(auto i:mp){
adj[i.f.f].pb({i.f.s,i.s});
adj[i.f.s].pb({i.f.f,i.s});
}*/
for(int i=1;i<=n;i++){
if(vis[i])continue;
have=0,z=0,x=i,mx=0;
dfs(i,-1);
pointer=0;
dfs1(x,-1);
sort(cycle,cycle+pointer);
reverse(cycle,cycle+pointer);
for(int j=0;j<pointer;j++){
dp1[up[cycle[j].s]]=max(dp1[up[cycle[j].s]],dp1[cycle[j].s]+dup[cycle[j].s]);
mx=max(mx,dp1[cycle[j].s]);
m1=m2=0;
for(auto k:adj[cycle[j].s]){
if(k.f==up[cycle[j].s])continue;
if(cycle[j].s==x&&k.f==y)continue;
if(cycle[j].s==y&&k.f==x)continue;
if(dp1[k.f]+k.s>=m1)m2=m1,m1=dp1[k.f]+k.s;
else if(dp1[k.f]+k.s>=m2)m2=dp1[k.f]+k.s;
}
mx=max(mx,m1+m2);
}
if(have){
pointer=0;
while(y!=x){
cycle[pointer++]={y,dup[y]};
on[y]=1;
y=up[y];
}
cycle[pointer++]={x,0};
on[x]=1;
reverse(cycle,cycle+pointer);
suf[pointer-1]=0;
pref=0,prefmx=0;
for(int i=pointer-2;i>=0;i--)suf[i]=cycle[i+1].s+suf[i+1];
for(int i=0;i<pointer;i++){
dp1[cycle[i].f]=0;
for(auto j:adj[cycle[i].f])if(!on[j.f])dp1[cycle[i].f]=max(dp1[cycle[i].f],dp1[j.f]+j.s);
}
for(int i=pointer-1;i>=0;i--){
suf[i]=suf[i]+dp1[cycle[i].f];
if(i+1<pointer)suf[i]=max(suf[i],suf[i+1]);
}
for(int i=0;i<pointer;i++){
pref+=cycle[i].s;
prefmx=max(prefmx,pref+dp1[cycle[i].f]);
if(i+1<pointer)mx=max(mx,prefmx+suf[i+1]+z);
}
}
ans+=mx;
}
cout<<ans<<'\n';
}
