#include <bits/stdc++.h>
using namespace std;
typedef long long i64; 
const int N = 2e5 + 5, B = 505;
const i64 INF = 1e18; 

int n, val[N];
vector<pair<int, int>> G[N]; 
i64 f[N][4], h[B * 2][2], g[B * 2][2];
mt19937 Rand(time(0));

inline void ckmax(i64 &x, i64 y) { x = max(x, y); }
inline void dfs(int x, int fa) {
    vector<int> v;
    for (auto [y, w] : G[x]) if (y != fa)
        val[y] = w, dfs(y, x), v.push_back(y); 
    shuffle(v.begin(), v.end(), Rand); 
    memset(g, -0x3f, sizeof g); g[B][0] = 0; // 1 - 3
    for (int y : v) {
        for (int j = 0; j <= B * 2; ++j) h[j][0] = h[j][1] = -INF; 
        for (int j = 1; j < B * 2; ++j) for (int k : {0, 1}) if (g[j][k] > -INF)
            ckmax(h[j][k], g[j][k] + f[y][0]), 
            ckmax(h[j + 1][k], g[j][k] + f[y][1]), 
            ckmax(h[j][k ^ 1], g[j][k] + f[y][2]), 
            ckmax(h[j - 1][k], g[j][k] + f[y][3]); 
        for (int j = 0; j <= B * 2; ++j) g[j][0] = h[j][0], g[j][1] = h[j][1];
    }
    if (x > 1) f[x][0] = max({0ll, g[B][0], g[B - 1][0] + val[x]}); 
    else f[x][0] = max(0ll, g[B][0]); 
    f[x][1] = max(0ll, g[B][0]) + val[x]; 
    f[x][2] = g[B + 1][0] + val[x]; 
    f[x][3] = g[B][1] + val[x]; 
}

int main(void) {
    ios::sync_with_stdio(0); 
    cin >> n; 
    for (int i = 1; i < n; ++i) {
        int u, v, w; cin >> u >> v >> w; 
        G[u].emplace_back(v, w); G[v].emplace_back(u, w); 
    }
    dfs(1, 0);
    cout << f[1][0] << '\n'; 
    return 0;
}