#include<bits/stdc++.h>
using namespace std;
//#pragma GCC optimize("Ofast")

#define rep(i,n) for(ll i=0;i<n;i++)
#define repl(i,l,r) for(ll i=(l);i<(r);i++)
#define per(i,n) for(ll i=(n)-1;i>=0;i--)
#define perl(i,r,l) for(ll i=r-1;i>=l;i--)
#define fi first
#define se second
#define pb push_back
#define ins insert
#define pqueue(x) priority_queue<x,vector<x>,greater<x>>
#define all(x) (x).begin(),(x).end()
#define CST(x) cout<<fixed<<setprecision(x)
#define vtpl(x,y,z) vector<tuple<x,y,z>>
#define rev(x) reverse(x);
using ll=long long;
using vl=vector<ll>;
using vvl=vector<vector<ll>>;
using pl=pair<ll,ll>;
using vpl=vector<pl>;
using vvpl=vector<vpl>;
const ll MOD=1000000007;
const ll MOD9=998244353;
const int inf=1e9+10;
const ll INF=4e18;
//const ll dy[9]={1,0,-1,0,1,1,-1,-1,0};
//const ll dx[9]={0,1,0,-1,1,-1,1,-1,0};
template<class T> inline bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
template<class T> inline bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

int main(){
    ll n;cin >> n;
    vvpl g(n);
    rep(i,n-1){
        ll a,b,w;cin >> a >> b >> w;a--;b--;
        g[a].emplace_back(make_pair(b,w));
        g[b].emplace_back(make_pair(a,w));
    }
    vl dist(n);
    auto dfs=[&](auto &self,ll v,ll par)->void {
        for(auto p:g[v]){
            if(p.first==par)continue;
            dist[p.first]=dist[v]+p.second;
            self(self,p.first,v);
        }
    };
    dfs(dfs,0,-1);
    auto p=max_element(all(dist))-dist.begin();
    rep(i,n)dist[i]=0;
    dfs(dfs,p,-1);
    cout << *max_element(all(dist)) << endl;
}