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#include <bits/stdc++.h>
#define MP make_pair
#define PB push_back
#define int long long
#define st first
#define nd second
#define rd third
#define FOR(i, a, b) for(int i =(a); i <=(b); ++i)
#define RE(i, n) FOR(i, 1, n)
#define FORD(i, a, b) for(int i = (a); i >= (b); --i)
#define REP(i, n) for(int i = 0;i <(n); ++i)
#define VAR(v, i) __typeof(i) v=(i)
#define FORE(i, c) for(VAR(i, (c).begin()); i != (c).begin(); ++i)
#define ALL(x) (x).begin(), (x).begin()
#define SZ(x) ((int)(x).size())
#define __builtin_ctz __builtin_ctzll
#define __builtin_clz __builtin_clzll
#define __builtin_popcount __builtin_popcountll
using namespace std;
template<typename TH> void _dbg(const char* sdbg, TH h) { cerr<<sdbg<<"="<<h<<"\n"; }
template<typename TH, typename... TA> void _dbg(const char* sdbg, TH h, TA... t) {
  while(*sdbg != ',') { cerr<<*sdbg++; } cerr<<"="<<h<<","; _dbg(sdbg+1, t...);
}
#ifdef LOCAL
#define debug(...) _dbg(#__VA_ARGS__, __VA_ARGS__)
#define debugv(x) {{cerr <<#x <<" = "; FORE(itt, (x)) cerr <<*itt <<", "; cerr <<"\n"; }}
#else
#define debug(...) (__VA_ARGS__)
#define debugv(x)
#define cerr if(0)cout
#endif
#define left ____left
#define hash ____hash
#define exchange dupa
typedef long long ll;
typedef long double LD;
typedef pair<int, int> PII;
typedef pair<ll, ll> PLL;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<ll> VLL;
typedef vector<pair<int, int> > VPII;
typedef vector<pair<ll, ll> > VPLL;

template<class C> void mini(C&a4, C b4){a4=min(a4, b4); }
template<class C> void maxi(C&a4, C b4){a4=max(a4, b4); }
template<class T1, class T2>
ostream& operator<< (ostream &out, pair<T1, T2> pair) { return out << "(" << pair.first << ", " << pair.second << ")";}
template<class A, class B, class C> struct Triple { A first; B second; C third;
  bool operator<(const Triple& t) const { if (st != t.st) return st < t.st; if (nd != t.nd) return nd < t.nd; return rd < t.rd; } };
template<class T> void ResizeVec(T&, vector<int>) {}
template<class T> void ResizeVec(vector<T>& vec, vector<int> sz) {
  vec.resize(sz[0]); sz.erase(sz.begin()); if (sz.empty()) { return; }
  for (T& v : vec) { ResizeVec(v, sz); }
}
typedef Triple<int, int, int> TIII;
template<class A, class B, class C>
ostream& operator<< (ostream &out, Triple<A, B, C> t) { return out << "(" << t.st << ", " << t.nd << ", " << t.rd << ")"; }
template<class T> ostream& operator<<(ostream& out, vector<T> vec) { out<<"("; for (auto& v: vec) out<<v<<", "; return out<<")"; }
template<class T> ostream& operator<<(ostream& out, set<T> vec) { out<<"("; for (auto& v: vec) out<<v<<", "; return out<<")"; }
template<class L, class R> ostream& operator<<(ostream& out, map<L, R> vec) { out<<"("; for (auto& v: vec) out<<v<<", "; return out<<")"; }

const int N = 2e5 + 5;
VPII slo[N];
int dp[N][4]; // dp[v][c] - najwiekszy zysk jaki mozna uzyskac w poddrzewie v majac niedokonczona sciezke w dol o dlugosci c
int vis[N];
const int kInf = 1e12;
int from_to[4][4];
typedef array<int, 4> A;
set<PII> exchange[4][4];
set<PII> merged02[4][4];
void Dfs(int v) {
  vis[v] = 1;
  vector<A> sons;
  for (auto e : slo[v]) {
    int nei = e.st;
    int cost = e.nd;
    if (vis[nei]) { continue; }
    Dfs(nei);
    A son;
    REP (c, 4) {
      son[c] = cost + dp[nei][(c + 3) % 4];
    }
    maxi(son[0], dp[nei][0]);
    sons.PB(son);
  }
  A B;
  REP (tr, 4) {
    B[tr] = -kInf / 2;
  }
  REP (artificial, 4) {
    int best = -kInf;
    sons.PB(B);
    sons.back()[artificial] = 0;
    //debug(v, artificial, sons);
    REP (x, 4) {
      REP (y, 4) {
        exchange[x][y].clear();
        merged02[x][y].clear();
      }
    }
    int score = 0;
    int parity = 0;
    VI where(SZ(sons), -1);
    function<void(int)> Del = [&](int who) {
      int ind = where[who];
      where[who] = -1;
      auto& vec = sons[who];
      score -= vec[ind];
      if (ind == 2) { parity ^= 1; }
      int i2 = ind;
      if (ind == 2) { i2 = 0; }
      REP (to, 4) {
        if (to == ind) { continue; }
        assert(exchange[ind][to].erase({vec[ind] - vec[to], who}));
        int t2 = to;
        if (to == 2) { t2 = 0; }
        merged02[i2][t2].erase({vec[ind] - vec[to], who});
      }
    };
    function<void(int, int)> Add = [&](int who, int ind) {
      auto& vec = sons[who];
      score += vec[ind];
      assert(where[who] == -1);
      where[who] = ind;
      if (ind == 2) { parity ^= 1; }
      int i2 = ind;
      if (ind == 2) { i2 = 0; }
      REP (to, 4) {
        if (to == ind) { continue; }
        exchange[ind][to].insert({vec[ind] - vec[to], who});
        int t2 = to;
        if (to == 2) { t2 = 0; }
        merged02[i2][t2].insert({vec[ind] - vec[to], who});
      }
    };
    function<void(int, int)> Move = [&](int who, int to) {
      Del(who);
      Add(who, to);
    };
    function<void()> UpdTable = [&]() {
      REP (from, 4) {
        REP (to, 4) {
          if (from == to) { continue; }
          if (exchange[from][to].empty()) {
            from_to[from][to] = -kInf;
          } else {
            from_to[from][to] = -exchange[from][to].begin()->st;
          }
        }
      }
    };
    REP (i, SZ(sons)) {
      auto& vec = sons[i];
      if (vec[0] > vec[2]) {
        Add(i, 0);
      } else {
        Add(i, 2);
      }
    }
    FOR (k, 0, SZ(sons) / 2) {
      UpdTable();
      if (parity == 0) {
        maxi(best, score);
        //debug(k, score);
      } else {
        int cand = -kInf;
        maxi(cand, from_to[0][2]);
        maxi(cand, from_to[2][0]);
        maxi(cand, from_to[0][3] + from_to[3][1] + from_to[1][2]);
        maxi(cand, from_to[0][1] + from_to[1][2]);
        maxi(cand, from_to[2][1] + from_to[1][0]);
        maxi(cand, from_to[2][1] + from_to[1][3] + from_to[3][0]);
        maxi(cand, from_to[0][1] + from_to[1][3] + from_to[3][2]);
        maxi(cand, from_to[2][3] + from_to[3][1] + from_to[1][0]);
        maxi(cand, from_to[0][3] + from_to[3][2]);
        maxi(cand, from_to[2][3] + from_to[3][0]);
        maxi(best, cand + score);
        assert(cand <= 0);
      }
      if (k == SZ(sons) / 2) { break; }
      assert(SZ(merged02[0][1]) == SZ(sons) - 2 * k);
      int c1 = -kInf;
      int c11 = -kInf;
      int c12 = -kInf;
      PII best_to_1 = *merged02[0][1].begin();
      PII best_to_3 = *merged02[0][3].begin();
      if (best_to_1.nd != best_to_3.nd) {
        c1 = -best_to_1.st - best_to_3.st;
      } else {
        c11 = -best_to_1.st - next(merged02[0][3].begin())->st;
        c12 = -next(merged02[0][1].begin())->st - best_to_3.st;
      }
      int c2 = -kInf, c3 = -kInf;
      if (k > 0) {
        c2 = -merged02[0][1].begin()->st - next(merged02[0][1].begin())->st - merged02[1][3].begin()->st; // 1->3, 02->1, 02->1
        c3 = -merged02[0][3].begin()->st - next(merged02[0][3].begin())->st - merged02[3][1].begin()->st; // 3->1, 02->3, 02->3
      }
      int M = max({c1, c11, c12, c2, c3});
      if (c1 == M) {
        Move(best_to_1.nd, 1);
        Move(best_to_3.nd, 3);
      } else if (c11 == M) {
        Move(next(merged02[0][3].begin())->nd, 3);
        Move(best_to_1.nd, 1);
      } else if (c12 == M) {
        Move(next(merged02[0][1].begin())->nd, 1);
        Move(best_to_3.nd, 3);
      } else if (c2 == M) {
        Move(merged02[1][3].begin()->nd, 3);
        Move(next(merged02[0][1].begin())->nd, 1);
        Move(merged02[0][1].begin()->nd, 1);
      } else {
        assert(c3 == M);
        Move(merged02[3][1].begin()->nd, 1);
        Move(next(merged02[0][3].begin())->nd, 3);
        Move(merged02[0][3].begin()->nd, 3);
      }
    }
    dp[v][(4 - artificial) % 4] = best;
    sons.pop_back();
  }
  //debug(v);
//   REP (i, 4) {
//     cerr<<dp[v][i]<<" ";
//   }
//   cerr<<endl;
}
int32_t main() {

  ios_base::sync_with_stdio(0);
  cout << fixed << setprecision(10);
  cerr << fixed << setprecision(10);
  cin.tie(0);
  //double beg_clock = 1.0 * clock() / CLOCKS_PER_SEC;
//#define TEST
  int n;
#ifdef TEST
  n = 2e5;
  int R = 1000000;
#else
  cin>>n;
#endif
  RE (i, n - 1) {
    int a, b, c;
#ifndef TEST
    cin>>a>>b>>c;
#else
    a = i + 1;
    b = 1 + rand() % i;
    c = -R + rand() % (2 * R);
#endif
    slo[a].PB({b, c});
    slo[b].PB({a, c});
  }
  Dfs(1);
  cout<<dp[1][0]<<endl;
  

  
  
  
  return 0;
}