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#include <algorithm>
#include <iostream>
#include <array>
#include <cassert>
#include <vector>
using namespace std;

const int MAXN = 200001;
const int MAXT = 1600;
const long long INF = 1000000000000000000;

#define FOR(i, n) for(int i = 0, __n = (n); i < __n; i++)


using Edge = pair<int, long long>;

using Top = array<long long, 4>;
const Top LEAF = {0, -INF, -INF, -INF};
const Top FORBIDDEN = {-INF, -INF, -INF, -INF};

ostream& operator<<(ostream& os, const Top& t)
{
  os << "{" << t[0] << ", " << t[1] << ", " << t[2] << ", " << t[3] << "}";
  return os;
}




template<class T> const T& max(const T& a, const T&b, const T&c, const T&d) {
  return max(max(a,b), max(c,d));
}


Top combine(vector<Top> & Res) {
  
  int n = Res.size();
  
  random_shuffle(Res.begin(), Res.end());
  // cout << "PRE " << n << endl;
  // FOR(i, n) {
  //   cout << Res[i] << endl;
  // }
  int MID = n+1;
  vector<long long> T[2] = {vector<long long> (2*MID+3, -INF), vector<long long> (2*MID+3, -INF)};
  vector<long long> T1[2] = {vector<long long> (2*MID+3, -INF), vector<long long> (2*MID+3, -INF)};
  T[0][MID] = 0;

  for (int i = 0; i < n; i++) {
    int lim = min(i+1, MAXT);
    for (int j = -lim; j <= +lim; j++) {
      FOR(p, 2) {
        T1[p][MID+j] = max(
          T[!p][MID+j] + Res[i][2],
          T[p][MID+j-1] + Res[i][3],
          T[p][MID+j+1] + Res[i][1],
          T[p][MID+j] + Res[i][0]
        );
      //  cout << "T(" << i+1 << "," << p << "," << j << ") = " << T1[p][MID+j] << endl;
      }
      
    }
    swap(T1[0], T[0]);
    swap(T1[1], T[1]);
  }
  // cout << "POST " << n << endl;

  Top r = {
    T[0][MID],
    T[0][MID-1],
    T[1][MID],
    T[0][MID+1]
  };
  // cout << " = " << r << endl;
  return r;

}


Top extend(Top a, long long val) {
  return {
    max(a[0], a[3] + val),
    a[0] + val,
    a[1] + val,
    a[2] + val
  };
}

struct Node {
  vector<Edge> V;
  int state;
  Top value;
  Node():state(0){}

} N[MAXN];

using para = pair<int,int>;


int main() {
  ios_base::sync_with_stdio(0);
  int n; 
  cin >> n;

  int a, b; long long v;
  FOR(i, n-1) {
    cin >> a >> b >> v;
    N[a-1].V.push_back(Edge(b-1, v));
    N[b-1].V.push_back(Edge(a-1, v));
  }

  vector<int> S;
  S.push_back(0);
  N[0].state = 1;

  while(!S.empty()) {
    int i = S.back();
    if(N[i].state == 1) {
      N[i].state = 2;
      FOR(j, N[i].V.size()) {
        if(N[N[i].V[j].first].state == 0) {
          S.push_back(N[i].V[j].first);
          N[N[i].V[j].first].state = 1;
        }
      }
    } else if(N[i].state == 2) {
      vector<Top> Res;

      FOR(j, N[i].V.size()) {
        int k = N[i].V[j].first;

        if(N[k].state == 3) {
          Top p = extend(N[k].value, N[i].V[j].second);
          Res.push_back(p);
        }
      }
      N[i].state = 3;
      N[i].value = combine(Res);
      S.pop_back();
    }
  }



  cout << N[0].value[0] << endl;;
}