#include <bits/stdc++.h>
#define io cin.tie(0), cout.tie(0), ios::sync_with_stdio(false)
#define LL long long
#define ULL unsigned long long
#define EPS 1e-8
#define INF 0x7fffffff
#define SUB -INF - 1
using namespace std;
const int N = 100005;
struct edge
{
    int to, w;
};
vector<edge> e[N];
int dp[N];
int maxlen = 0;
bool vis[N];
void dfs(int u)
{
    vis[u] = true;
    for(int i = 0; i < e[u].size(); i++)
    {
        int v = e[u][i].to, edge = e[u][i].w;
        if (vis[v])
            continue;
        dfs(v);
        maxlen = max(maxlen, dp[u] + dp[v] + edge);
        dp[u] = max(dp[u], dp[v] + edge);
    }
    return;
}
int main()
{
    int n;
    cin >> n;
    for (int i = 0; i < n - 1; i++)
    {
        int a, b, w;
        cin >> a >> b >> w;
        e[a].push_back({b, w});
        e[b].push_back({a, w});
    }
    dfs(1);
    cout << maxlen << endl;
    return 0;
}