#include <iostream>
#include <vector>
using namespace std;
typedef long long llong;
const int MAXN = 2e5 + 10;
const llong INF = 4e18 + 10;
struct Edge
{
int to;
int cost;
Edge(){};
Edge(int to, int cost)
{
this->to = to;
this->cost = cost;
}
};
int n;
vector < Edge > adj[MAXN];
llong dp[MAXN][2];
llong up[MAXN][2];
pair < llong, int > minch[MAXN][2];
llong ans;
void read()
{
cin >> n;
for(int i = 1; i < n; i++)
{
int u, v, cost;
cin >> u >> v >> cost;
adj[u].push_back(Edge(v, cost));
adj[v].push_back(Edge(u, cost));
}
}
void dfs(int u, int par)
{
minch[u][0] = minch[u][1] = {INF, 0};
for(Edge &e : adj[u])
{
int v = e.to;
int cost = e.cost;
if(v == par)
continue;
dfs(v, u);
llong cur = max(dp[v][0], dp[v][1] + cost);
dp[u][0] += cur;
pair < llong, int > opt = {cur - dp[v][0] - cost, v};
if(opt < minch[u][0])
{
minch[u][1] = minch[u][0];
minch[u][0] = opt;
}
else if(opt < minch[u][1])
{
minch[u][1] = opt;
}
}
if(adj[u].size() == 1)
dp[u][1] = -INF;
else
dp[u][1] = dp[u][0] - minch[u][0].first;
}
void dfs2(int u, int par)
{
for(Edge &e : adj[u])
{
int v = e.to;
int cost = e.cost;
if(v == par)
continue;
llong cur = max(dp[v][0], dp[v][1] + cost);
llong f0 = dp[u][0] + up[u][0] - cur;
llong f1 = dp[u][0] + up[u][1] - cur;
if(u == 1)
f1 = -INF;
llong opt = dp[u][1] + up[u][0] - cur;
if(minch[u][0].second == v)
{
opt += minch[u][0].first;
opt -= minch[u][1].first;
}
f1 = max(f1, opt);
up[v][0] = max(f0, f1 + cost);
up[v][1] = f0 + cost;
ans = max(ans, up[v][0] + dp[v][0]);
dfs2(v, u);
}
}
void solve()
{
dfs(1, 1);
ans = dp[1][0];
dfs2(1, 1);
cout << ans << endl;
}
int main()
{
read();
solve();
return 0;
}
