#include<bits/stdc++.h>
using namespace std;
#define all(x) x.begin() , x.end()
typedef long long ll;
typedef pair<ll , ll> pll;
const ll maxn = 1e5 + 16 , inf = 2e16;
ll dp[maxn][2] , w[maxn];
vector<pll> adj[maxn];
void DFS(ll r , ll par){
ll res = 0 , mx1 = -inf , mx2 = -inf;
for(auto p : adj[r]){
ll i = p.first , w = p.second;
if(i == par) continue;
DFS(i , r);
ll h = max(dp[i][0] , dp[i][1] + w) , o = dp[i][0] + w - h;
res += h;
if(o > mx2){
mx2 = o;
}
if(o > mx1){
swap(mx1 , mx2);
}
}
dp[r][1] = res + mx1;
dp[r][0] = max(res , res + mx1 + mx2);
return;
}
int main(){
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
ll n;
cin>>n;
for(ll i = 1 ; i < n ; i++){
ll v , u , w;
cin>>v>>u>>w; v--; u--;
adj[v].push_back({u , w}); adj[u].push_back({v , w});
}
DFS(0 , -1);
cout<<dp[0][0]<<'\n';
return 0;
}
