#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
using namespace std;

struct arco_t {
    int u, v, w;
};
int N;
vector<vector<arco_t>> G;
int bfs(int start) {
    vector<int> distances(N+1, -1);
    vector<bool> visited(N+1, false);

    queue<int> coda;
    coda.push(start);
    distances[start] = 0;
    int far = 0;
    while (!coda.empty()) {
        int nodo = coda.front();
        coda.pop();
        visited[nodo] = true;
        for (auto x : G[nodo]) {
            if (visited[x.v]) continue;
            int cost = x.w + distances[nodo];
            far = max(cost, far);
            distances[x.v] = cost;
            coda.push(x.v);
        }
    }
    return far;
}

int main() {
    ifstream cin("input.txt");
    ofstream out("output.txt");

    cin >> N;

    G.resize(N+1);

    for (int i = 1; i < N; i++) {
        int a, b, l;
        cin >> a >> b >> l;
        G[a].push_back({a, b, l});
        G[b].push_back({b, a, l});
    }

    int longest = 0;
    for (int i = 1; i <= N; i++) {
        longest = max(bfs(i), longest);
    }

    out << longest;
    out.close();
    return 0;
}