#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define pb push_back
const int N = 2e5 + 5;
const ll inf = 1e12;
ll dp[N][2][2];
vector<array<int, 2>> g[N];
void dfs(int s, int e = -1) {
dp[s][0][0] = dp[s][1][0] = dp[s][1][1] = 0, dp[s][0][1] = -inf;
for (auto [u, w] : g[s]) {
if (u == e) continue;
dfs(u, s);
dp[s][0][0] += max(dp[u][0][0], dp[u][1][0] + w);
}
ll bs = -inf, bs2 = -inf;
for (auto [u, w] : g[s]) {
if (u == e) continue;
bs = max(bs, dp[u][0][0] + w - max(dp[u][0][0], dp[u][1][0] + w));
dp[s][1][0] += max(dp[u][0][0], dp[u][1][0] + w);
}
dp[s][1][0] += bs;
bs = bs2 = -inf;
vector<array<ll, 2>> V1 = {{-inf, 0}, {-inf, 0}}, V2 = {{-inf, 0}, {-inf, 0}};
ll S = 0;
for (auto [u, w] : g[s]) {
if (u == e) continue;
V1.pb({dp[u][0][0] + w - max(dp[u][0][0], dp[u][1][0] + w), u});
V2.pb({dp[u][0][1] + w - max(dp[u][0][0], dp[u][1][0] + w), u});
S += max(dp[u][0][0], dp[u][1][0] + w);
bs = max(bs, max(dp[u][1][1] + w, dp[u][0][1]) - max(dp[u][0][0], dp[u][1][0] + w));
}
sort(V1.begin(), V1.end());
sort(V2.begin(), V2.end());
int sz = V1.size();
// if (s == 1) {
// for (auto [a, b] : V1) cout << a << ' ' << b << "||";
// cout << '\n';
// for (auto [a, b] : V2) cout << a << ' ' << b << "||";
// cout << '\n';
// cout << S << ' ' << bs << '\n';
// }
dp[s][0][1] = S + max({bs, V1[sz-1][0] + V1[sz-2][0], (V1[sz-1][1] == V2[sz-1][1] ? max(V1[sz-1][0] + V2[sz-2][0], V1[sz-2][0] + V2[sz-1][0]) : V1[sz-1][0] + V2[sz-1][0])});
bs = -inf;
for (auto [u, w] : g[s]) {
if (u == e) continue;
bs = max(bs, dp[u][0][1] + w - max(dp[u][0][0], dp[u][1][0] + w));
dp[s][1][1] += max(dp[u][0][0], dp[u][1][0] + w);
}
dp[s][1][1] += bs;
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
int n;
cin >> n;
for (int i = 1; i < n; ++i) {
int u, v, w;
cin >> u >> v >> w;
g[u].pb({v, w});
g[v].pb({u, w});
}
dfs(1);
cout << max(dp[1][0][0], dp[1][0][1]) << '\n';
}
