#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main() {
    int N;
    cin >> N;
    vector<vector<ll>> dist(N + 1, vector<ll>(N + 1, 1e18));
    for (int i = 1; i <= N; ++i) dist[i][i] = 0;
    for (int i = 0; i < N - 1; ++i) {
        int u, v;
        ll w;
        cin >> u >> v >> w;
        dist[u][v] = w;
        dist[v][u] = w;
    }
    for (int k = 1; k <= N; ++k) {
        for (int i = 1; i <= N; ++i) {
            for (int j = 1; j <= N; ++j) {
                if (dist[i][k] != 1e18 && dist[k][j] != 1e18) {
                    dist[i][j] = min(dist[i][j], dist[i][k] + dist[k][j]);
                }
            }
        }
    }
    ll max_dist = -1e18;
    for (int i = 1; i <= N; ++i) {
        for (int j = 1; j <= N; ++j) {
            if (dist[i][j] != 1e18) {
                max_dist = max(max_dist, dist[i][j]);
            }
        }
    }
    cout << max_dist << endl;
    return 0;
}