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#include <bits/stdc++.h>
#define REP(i,n) for (int _n=(n), i=0;i<_n;++i)
#define FOR(i,a,b) for (int i=(a),_b=(b);i<=_b;++i)
#define FORD(i,a,b) for (int i=(a),_b=(b);i>=_b;--i)
#define TRACE(x) std::cerr << "TRACE(" #x ")" << std::endl;
#define DEBUG(x) std::cerr << #x << " = " << (x) << std::endl;
using std::int64_t;

void init_io() {
  std::cin.tie(nullptr);
  std::ios::sync_with_stdio(false);
}

namespace chacha_private {
  template <int shift>
  void rotate_left(std::uint32_t &x) {
    x = (x << shift) | (x >> (32 - shift));
  }

  inline void quarter_round(std::uint32_t &a, std::uint32_t &b, std::uint32_t &c, std::uint32_t &d) {
    a += b;
    d ^= a;
    rotate_left<16>(d);
    c += d;
    b ^= c;
    rotate_left<12>(b);
    a += b;
    d ^= a;
    rotate_left<8>(d);
    c += d;
    b ^= c;
    rotate_left<7>(b);
  }
}

template<int rounds>
void chacha(const std::uint32_t (&key)[8],
            const std::uint64_t nonce,
            const std::uint64_t counter,
            std::uint32_t (&output)[16])
{
  static_assert(rounds == 8 || rounds == 12 || rounds == 20);

  using namespace chacha_private;

  std::uint32_t input[16];
  std::memcpy(input + 0, "expand 32-byte k", 4 * sizeof(std::uint32_t));
  std::memcpy(input + 4, key, 8 * sizeof(std::uint32_t));
  std::memcpy(input + 12, &counter, 2 * sizeof(std::uint32_t));
  std::memcpy(input + 14, &nonce, 2 * sizeof(std::uint32_t));

  std::uint32_t x[16];
  std::memcpy(x, input, 16 * sizeof(std::uint32_t));

  for (int double_round = 0; double_round < rounds / 2; ++double_round) {
    quarter_round(x[0], x[4], x[8], x[12]);
    quarter_round(x[1], x[5], x[9], x[13]);
    quarter_round(x[2], x[6], x[10], x[14]);
    quarter_round(x[3], x[7], x[11], x[15]);

    quarter_round(x[0], x[5], x[10], x[15]);
    quarter_round(x[1], x[6], x[11], x[12]);
    quarter_round(x[2], x[7], x[8], x[13]);
    quarter_round(x[3], x[4], x[9], x[14]);
  }

  for (int i = 0; i < 16; ++i) {
    x[i] += input[i];
  }

  std::memcpy(output, x, 16 * sizeof(std::uint32_t));
}

class ChachaRandom {
public:
  using result_type = std::uint32_t;
  constexpr result_type min() { return 0; }
  constexpr result_type max() { return std::numeric_limits<result_type>::max(); }

  explicit ChachaRandom(const std::uint32_t (&key)[8]);
  std::uint32_t operator()() {
    if (m_buffer_next == 16) {
      refill_buffer();
    }
    return m_buffer[m_buffer_next++];
  }

private:
  void refill_buffer();

  std::uint32_t m_chacha_key[8];
  static constexpr std::uint64_t m_chacha_nonce = 0;
  std::uint64_t m_chacha_counter = 0;

  std::uint32_t m_buffer[16];
  int m_buffer_next = 16;
};

ChachaRandom::ChachaRandom(const std::uint32_t (&key)[8]) {
  std::memcpy(m_chacha_key, key, 8 * sizeof(std::uint32_t));
}

void ChachaRandom::refill_buffer() {
  chacha<8>(m_chacha_key, m_chacha_nonce, m_chacha_counter++, m_buffer);
  m_buffer_next = 0;
}

ChachaRandom rng {{
  0x6ef8bdb2, 0x29173e28, 0x3045720a, 0x1554270c, 0xf4b3032, 0xbbe13b97, 0xf88df4ec, 0x3a83bd73,
}};

constexpr int root = 0;
constexpr int vertex_none = -1;
constexpr int64_t infinity = 1LL << 60;

struct Vertex {
  int parent = vertex_none;
  int edge_begin = 0;
  int edge_end = 0;
  int64_t subtree_value[4] = {}; // index = extra path from root
};

struct Edge {
  int from = 0;
  int to = 0;
  int weight = 0;
};

int num_vertices;
std::vector<Vertex> vertices;
std::vector<Edge> edges;

void read_tree() {
  std::cin >> num_vertices;
  vertices.resize(num_vertices);
  edges.reserve(2 * (num_vertices - 1));
  REP(i, num_vertices - 1) {
    Edge edge;
    std::cin >> edge.from >> edge.to >> edge.weight;
    --edge.from;
    --edge.to;
    edges.push_back(edge);
    std::swap(edge.from, edge.to);
    edges.push_back(edge);
  }
  std::sort(edges.begin(), edges.end(), [](const Edge &a, const Edge &b) {
      return a.from < b.from;
  });
  int edge_next = 0;
  REP(i, num_vertices) {
    Vertex &v = vertices[i];
    v.edge_begin = edge_next;
    while (edge_next != int(edges.size()) && edges[edge_next].from == i) {
      ++edge_next;
    }
    v.edge_end = edge_next;
  }
  assert(edge_next == int(edges.size()));
}

void initialize(int64_t *new_score, int64_t *score, int len, int64_t add) {
  int i = 0;
  while (i + 4 <= len) {
    auto score0 = score[i];
    auto score1 = score[i+1];
    auto score2 = score[i+2];
    auto score3 = score[i+3];
    new_score[i] = score0 + add;
    new_score[i+1] = score1 + add;
    new_score[i+2] = score2 + add;
    new_score[i+3] = score3 + add;
    i += 4;
  }
  while (i < len) {
    new_score[i] = score[i] + add;
    i += 1;
  }
}

void improve(int64_t *new_score, int64_t *score, int len, int64_t add) {
  int i = 0;
  while (i + 4 <= len) {
    auto score0 = score[i];
    auto score1 = score[i+1];
    auto score2 = score[i+2];
    auto score3 = score[i+3];
    new_score[i] = std::max(new_score[i], score0 + add);
    new_score[i+1] = std::max(new_score[i+1], score1 + add);
    new_score[i+2] = std::max(new_score[i+2], score2 + add);
    new_score[i+3] = std::max(new_score[i+3], score3 + add);
    i += 4;
  }
  while (i < len) {
    new_score[i] = std::max(new_score[i], score[i] + add);
    i += 1;
  }
}

void solve_vertex(Vertex &v) {
  // Worst case: 50000 * 3 + 50000 * 1.
  // Random walk +-1 of len 50000 has stddev 223.
  // 1000 is 4.47 sigma, good enough.
  static constexpr int max_bias = 1000;

  // score[p][max_bias + b] = best score for:
  // p = number of "2" children mod 2 
  // b = number of "3" children - number of "1" children
  static int64_t score[2][2 * max_bias + 1];
  static int64_t new_score[2][2 * max_bias + 1];

  REP(p, 2) REP(b, 2 * max_bias + 1) score[p][b] = -infinity;
  score[0][max_bias] = 0;

  std::shuffle(edges.begin() + v.edge_begin, edges.begin() + v.edge_end, rng);

  for (int edge_idx = v.edge_begin; edge_idx != v.edge_end; ++edge_idx) {
    const Edge &edge = edges[edge_idx];
    if (edge.to == v.parent) continue;
    const Vertex &child = vertices[edge.to];

    // Don't use edge.
    REP(p, 2) {
      initialize(new_score[p], score[p], 2 * max_bias + 1, child.subtree_value[0]);
    }

    // 0 = edge + 3 in child
    // parity = 0
    // bias = 0
    if (child.subtree_value[3] > -infinity/2) {
      REP(p, 2) {
        improve(new_score[p], score[p], 2 * max_bias + 1, edge.weight + child.subtree_value[3]);
      }
    }

    // 1 = edge + 0 in child
    // parity = 0
    // bias = -1
    if (child.subtree_value[0] > -infinity/2) {
      REP(p, 2) {
        improve(new_score[p], score[p] + 1, 2 * max_bias, edge.weight + child.subtree_value[0]);
      }
    }

    // 2 = edge + 1 in child
    // parity = 1
    // bias = 0 
    if (child.subtree_value[1] > -infinity/2) {
      REP(p, 2) {
        improve(new_score[p], score[p ^ 1], 2 * max_bias + 1, edge.weight + child.subtree_value[1]);
      }
    }

    // 3 = edge + 2 in child
    // parity = 0
    // bias = 1
    if (child.subtree_value[2] > -infinity/2) {
      REP(p, 2) {
        improve(new_score[p] + 1, score[p], 2 * max_bias, edge.weight + child.subtree_value[2]);
      }
    }

    std::memcpy(&score, &new_score, sizeof(score));
  }

  v.subtree_value[0] = score[0][max_bias];
  v.subtree_value[1] = score[0][max_bias - 1];
  v.subtree_value[2] = score[1][max_bias];
  v.subtree_value[3] = score[0][max_bias + 1];
}

enum class Stage {
  enter,
  finish,
};

struct StackElem {
  int vertex;
  Stage stage;
};

int64_t solve() {
  std::vector<StackElem> stack;
  stack.reserve(num_vertices);
  vertices[root].parent = vertex_none;
  stack.push_back(StackElem { root, Stage::enter });
  while (!stack.empty()) {
    StackElem elem = stack.back();
    stack.pop_back();
    Vertex &v = vertices[elem.vertex];
    if (elem.stage == Stage::enter) {
      stack.push_back(StackElem { elem.vertex, Stage::finish });
      for (int edge_idx = v.edge_begin; edge_idx != v.edge_end; ++edge_idx) {
        const Edge &edge = edges[edge_idx];
        if (edge.to == v.parent) continue;
        vertices[edge.to].parent = elem.vertex;
        stack.push_back(StackElem { edge.to, Stage::enter });
      }
    } else {
      solve_vertex(v);
    }
  }
  return vertices[root].subtree_value[0];
}

int main() {
  init_io();
  read_tree();
  const auto res = solve();
  std::cout << res << '\n';
}