/*input
5
1 2 10
1 3 40
1 4 15
1 5 20
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
*/
#include <algorithm>
#include <bitset>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <utility>
#include <vector>
using namespace std;
#define sp ' '
#define endl '\n'
#define fi first
#define se second
#define mp make_pair
#define int long long
#define N 200005
int n;
vector<vector<pair<int, int> > > a(N);
int dp[N][2];
int cal(int u, int p, bool up, int price) {
int &ret = dp[u][up];
if (ret != -1) return ret;
ret = 0;
int sum = 0;
for (int i = 0; i < a[u].size(); i++) {
int v = a[u][i].fi; if (v == p) continue;
sum += cal(v, u, 0, a[u][i].se);
}
ret = max(ret, sum);
if (!up) {
for (int i = 0; i < a[u].size(); i++) {
int v = a[u][i].fi; if (v == p) continue;
ret = max(ret, sum - cal(v, u, 0, a[u][i].se) + cal(v, u, 1, a[u][i].se) + a[u][i].se + price);
}
}
return ret;
}
int ans = 0;
void modify(int u, int p, int price) {
if (u != 1) {
dp[p][0] = dp[p][1] = -1;
dp[u][0] = dp[u][1] = -1;
ans = max(ans, cal(u, u, 1, 0));
}
else {
ans = max(ans, cal(u, u, 1, 0));
}
for (int i = 0; i < a[u].size(); i++) {
int v = a[u][i].fi; if (v == p) continue;
int x0 = dp[v][0], x1 = dp[v][1], y0 = dp[u][0], y1 = dp[u][1];
modify(v, u, a[u][i].se);
dp[v][0] = x0; dp[v][1] = x1; dp[u][0] = y0; dp[u][1] = y1;
}
}
signed main() {
ios_base::sync_with_stdio(false); cin.tie(0);
#ifdef UncleGrandpa
freopen("1test.inp", "r", stdin);
#endif
cin >> n;
for (int i = 1; i <= n - 1; i++) {
int u, v, c; cin >> u >> v >> c;
a[u].push_back(mp(v, c));
a[v].push_back(mp(u, c));
}
memset(dp, -1, sizeof(dp));
modify(1, 1, 0);
cout << ans << endl;
}
