#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5+10;
int n;
int d[maxn];
bool vis[maxn];
struct Edge{
    int v, weight;
};
vector<Edge> G[maxn];
int bfs(int u){
    for(int i=0; i<n; i++) d[i] = -1;
    memset(vis, 0, sizeof(vis));
    d[u] = 0;
    queue<int> q;
    q.push(u);
    vis[u] = true;
    int long_dis = -1;
    while(!q.empty()){
        int temp = q.front();
        q.pop();
        for(int i=0; i<G[temp].size(); i++){
            Edge e = G[temp][i];
            if(vis[e.v]) continue;
            else{
                if(d[e.v]<d[temp]+e.weight){
                    d[e.v]=d[temp]+e.weight;
                    q.push(e.v);
                    long_dis = e.v;
                    vis[e.v] = true;
                }
            }
        }
    }
    return long_dis;
}
void solve(){
    int p = bfs(0);
    int q = bfs(p);
    int ans = -1;
    for(int i=0; i<n; i++){
        ans = max(ans, d[i]);
    }
    printf("%d\n", ans);
}
int main()
{
    while(cin>>n){
        int u, v, weight;
        for(int i=0; i<n-1; i++){
            cin>>u>>v>>weight;
            G[u].push_back(Edge{v, weight});
            G[v].push_back(Edge{u, weight});
        }
        solve();
    }
    return 0;
}