#include <bits/stdc++.h>
#pragma GCC optimize ("O2")
#pragma GCC optimize ("unroll-loops")
using namespace std;
#define pii pair <int , int>
#define F first
#define S second
const int N = 2e5 + 10, inf = 1e9 + 5;
int dp[N][2], dpU[N][2], par[N], mx[N], E[N][3];
vector <int> g[N];
inline int adj(int v, int i) {return (v^E[i][0]^E[i][1]);}
void dfs(int v, int p = 0)
{
par[v] = p;
for (int i : g[v]) if (adj(v, i) != p) {
dfs(adj(v, i), v);
mx[adj(v, i)] = max(dp[adj(v, i)][1] + E[i][2], dp[adj(v, i)][0]);
dp[v][0] += mx[adj(v, i)];
}
for (int i : g[v]) if (adj(v, i) != p)
dp[v][1] = max(dp[v][1], dp[v][0] - mx[adj(v, i)] + dp[adj(v, i)][0] + E[i][2]);
}
void dfsUp(int v, int w = 0)
{
int p = par[v];
if (p == 0) dpU[v][0] = 0;
if (p != 0) {
dpU[v][0] = dpU[p][0] + dp[p][0] - mx[v];
for (int i : g[p]) if (adj(p, i) != v && adj(p, i) != par[p])
dpU[v][0] = max(dpU[v][0], dpU[p][0] + dp[p][0] - mx[adj(p, i)] + dp[adj(p, i)][0] + E[i][2] - mx[v] + w);
dpU[v][0] = max(dpU[v][0], dpU[p][1] + dp[p][0] - mx[v] + w);
dpU[v][1] = dpU[p][0] + dp[p][0] - mx[v] + w;
}
for (int i : g[v]) if (adj(v, i) != p) dfsUp(adj(v, i), E[i][2]);
}
int32_t main()
{
ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
int n; cin >> n;
for (int i = 0; i < n - 1; i++) {
cin >> E[i][0] >> E[i][1] >> E[i][2];
g[E[i][0]].push_back(i);
g[E[i][1]].push_back(i);
}
for (int i = 1; i <= n; i++) dp[i][1] = dpU[i][1] = -inf;
dfs(1), dfsUp(1);
int ans = 0;
for (int i = 1; i <= n; i++) ans = max(ans, dp[i][0] + dpU[i][0]);
printf("%d", ans);
return 0;
}
