#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define pii pair<int,int>
#define f first
#define s second
#define chmin(a, b) a = min(a,b)
#define chmax(a, b) a = max(a,b)
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define F0R(i, a) for (int i = 0; i < (a); i++)
#define all(x) x.begin(),x.end()
#define vec vector
const int MAX_N = 2e5;
vec<pii> adj[MAX_N];
ll dp_down[MAX_N][2], dp_up[MAX_N][2];
ll mx[MAX_N][2];//, mx[MAX_N][2];
ll ans = 0;
void dfs_down(int cur) {
dp_down[cur][0] = 0;
mx[cur][0] = mx[cur][1] = -1e16;
for (auto[x,w] : adj[cur]) {
adj[x].erase(find(all(adj[x]),make_pair(cur,w)));
dfs_down(x);
ll push = max(dp_down[x][1]+w,dp_down[x][0]);
//if (push>=mx[cur][0]) {mx[cur][1] = mx[cur][0]; mx[cur][0] = push;}
//else if (push>mx[cur][1]) {mx[cur][1] = push;}
dp_down[cur][0] += push;
ll ex = dp_down[x][0]+w-push;
if (ex>=mx[cur][0]) {mx[cur][1] = mx[cur][0]; mx[cur][0] = ex;}
else if (ex>mx[cur][1]) {mx[cur][1] = ex;}
}
chmax(dp_down[cur][1],dp_down[cur][0]+mx[cur][0]);
}
void dfs_up(int cur) {
chmax(ans,dp_down[cur][0]+dp_up[cur][0]);
chmax(ans,dp_down[cur][1]+dp_up[cur][1]);
for (auto[x,w] : adj[cur]) {
ll push = max(dp_down[x][1]+w,dp_down[x][0]);
ll down0 = dp_down[cur][0]-push;
ll ex = dp_down[x][0]+w-push;
ll down1 = down0+mx[cur][ex==mx[cur][0]];
dp_up[x][0] = dp_up[cur][0]+down0;
//chmax(dp_up[x][0],dp_up[cur][1]+down1);
chmax(dp_up[x][0],dp_up[cur][1]+down0+w);
chmax(dp_up[x][0],dp_up[cur][0]+down1+w);
dp_up[x][1] = dp_up[cur][0]+down0+w;
//chmax(dp_up[x][1],dp_up[cur][1]+down1+w);
dfs_up(x);
}
}
int main() {
ios::sync_with_stdio(false); cin.tie(0);
for (int i=0;i<MAX_N;i++) {
dp_down[i][1] = dp_up[i][1] = -1e10;
dp_down[i][0] = dp_up[i][0] = 0;
}
memset(mx,0,sizeof(mx));
int n; cin >> n;
for (int i=0;i<n-1;i++) {
int u, v, w; cin >> u >> v >> w;
adj[--u].pb({--v,w});
adj[v].pb({u,w});
}
dfs_down(0); dfs_up(0);
//cout<<dp_up[2][1];
//F0R(i,n) {cout<<dp_down[i][0]<<' ' << dp_down[i][1]<<'\n';}
cout << ans << '\n';
}
