// hmmm... na dige chizi baraye goftan namoonde
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define all(x) x.begin(), x.end()
#define pb push_back
#define fi first
#define se second
const int maxn5 = 3e5 + 10;
const int lg = 20;
const ll inf = 1e18;
ll dp[2][maxn5], ans = 0, fpar[2][maxn5];
vector <pair<int, int>> adj[maxn5];
void dfs2(int v, int par){
ll sum = 0;
ll smx = -inf, mx = -inf;
if(par != -1){
sum += fpar[0][v];
mx = max(mx, fpar[1][v] - fpar[0][v]);
}
for(auto [u, w] : adj[v]) if(u != par){
sum += dp[0][u];
ll val = dp[1][u] - dp[0][u];
if(val >= mx)
smx = mx, mx = val;
else
smx = max(smx, val);
}
ans = max(ans, sum);
for(auto [u, w] : adj[v]) if(u != par){
fpar[1][u] = w + sum - dp[0][u];
fpar[0][u] = max(sum - dp[0][u], w + sum - dp[0][u] + (mx == dp[1][u] - dp[0][u] ? smx : mx));
dfs2(u, v);
}
}
void dfs(int v, int par){
for(auto [u, w] : adj[v]) if(u != par){
dp[1][u] = w;
dfs(u, v);
dp[0][v] = max(dp[0][v] + dp[0][u], dp[1][v] + dp[1][u]);
dp[1][v] += dp[0][u];
}
}
int main(){
ios_base::sync_with_stdio(false); cin.tie(0);
int n; cin >> n;
for(int i = 0; i < n - 1; i ++){
int a, b, c; cin >> a >> b >> c;
a--; b--;
adj[a].pb({b, c});
adj[b].pb({a, c});
}
dfs(0, -1);
dfs2(0, -1);
cout << ans << endl;
}
/*
10
4 10 2
1 2 21
1 3 13
6 7 1
7 9 5
2 4 3
2 5 8
1 6 55
6 8 34
*/
