#include <iostream>
#include <algorithm>
#include <functional>
#include <cmath>
#include <vector>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <queue>
#include <ctime>
#include <cassert>
#include <complex>
#include <string>
#include <cstring>
#include <chrono>
#include <random>
#include <bitset>
#include <array>
#include<utility>
#include<stack>
#include <iomanip>
//#include<atcoder/all>
//using namespace atcoder;
using namespace std;
#define P pair<int,int>
#define Graph vector<vector<int>>
#define float long double
#define rep(i,a,b) for(int i=(a);i<(b);++i)
#define repi(itr,m) for(auto itr=(m).begin();itr!=(m).end();itr++)
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define vi vector<int>
#define int long long
const int INF=1e18;
int dx[8]={0,1,0,-1,-1,-1,1,1};
int dy[8]={1,0,-1,0,-1,1,-1,1};
#include <time.h>
template<typename T> inline bool chmax(T &a, T b) { return ((a < b) ? (a = b, true) : (false));}
template<typename T> inline bool chmin(T &a, T b) { return ((a > b) ? (a = b, true) : (false));}
struct point{
  int x,y;
};
void yn(bool t){
  if(t)cout<<"Yes"<<endl;
  else cout<<"No"<<endl;
}

int solve(){
  clock_t start = clock();
  int n;cin>>n;
  vector<vector<P>>g(n+1);
  rep(i,1,n){
    int u,v,w;cin>>u>>v>>w;
    g[u].push_back({v,w});
    g[v].push_back({u,w});
  }
  vector<int>dist1(n+1,-INF);
  dist1[3]=0;
  queue<P>pq;//to come
  pq.push({3,0});
  while(!pq.empty()){
    auto [to,come]=pq.front();
    pq.pop();
    for(auto [v,cost]:g[to]){
      if(v==come)continue;
      dist1[v]=dist1[to]+cost;
      pq.push({v,to});
    }
  }
  priority_queue<P>cnt;
  rep(i,1,n+1)cnt.push({dist1[i],i});
  int ans=-INF;
  
  while(1){
    auto [cost,idx]=cnt.top();
    cnt.pop();
    vector<int>dist2(n+1,-INF);
    dist2[idx]=0;
    queue<P>pq2;//to come
    pq2.push({idx,0});
    while(!pq2.empty()){
      auto [to,come]=pq2.front();
      pq2.pop();
      for(auto [v,cost]:g[to]){
        if(v==come)continue;
        dist2[v]=dist2[to]+cost;
        pq2.push({v,to});
      }
    }
    rep(i,1,n+1){
      ans=max(ans,dist2[i]);
      cnt.push({dist2[i],i});
    }
    clock_t end= clock();
    if(end-start>1900)break;
  }
  
  
  cout<<ans<<endl;
  assert(true);
  return 0;
}

signed main(){
  ios::sync_with_stdio(false);
  std::cin.tie(nullptr);
  solve();
}