#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll,ll> edge;
const ll INF = (1LL<<60);
ll ans=0;

ll n;
vector<edge> T[200000];

bool visited[200000];
ll x[200000];

ll dfs(ll p){
  visited[p]=true;
  ll maxm=0;
  
  for(int i=0;i<(int)T[p].size();i++){
    edge e=T[p][i];
    if(visited[e.first])continue;
    visited[e.first]=true;

    ll y = dfs(e.first)+e.second;
    ans=max(ans, maxm+y);
    maxm= max(maxm, y);
  }
  
  return maxm;
}

int main(){
  cin>>n;
  for(int i=0;i<n-1;i++){
    ll a,b,c;
    cin>>a>>b>>c;
    a--,b--;
    T[a].push_back( edge(b,c) );
    T[b].push_back( edge(a,c) );
  }
  for(int i=0;i<n;i++){
    visited[i]=false;
    x[i]=-INF;
  }

  
  dfs(0);
  cout<<ans<<endl;
  return 0;
}