#include <bits/stdc++.h>
using namespace std;
#define F first
#define S second
#define PB push_back
#define _sz(e) e.size()
#define pii pair <int , int>
#define FAST ios::sync_with_stdio(0); cin.tie(0);
const int maxn = 2e5 + 4 , N = 1e6 + 4 , mod = 1e9 + 7 , INF = 1e9;
int n , dp[maxn] , gp[maxn] , zp[maxn];
vector <pii> edges[maxn];
void dfs(int v , int p = -1 , int W = 0) {
for (auto u : edges[v]) {
if(u.F != p) dfs(u.F , v , u.S);
}
for (auto u : edges[v]) {
if(u.F != p) {
dp[v] += max(dp[u.F] , gp[u.F]);
}
}
for (auto u : edges[v]) {
if(u.F != p) {
int others = dp[v] - max(dp[u.F] , gp[u.F]);
gp[v] = max(gp[v] , dp[u.F] + u.S + W + others);
}
}
zp[v] = dp[v];
int mx1 = -INF , mx2 = -INF;
for (auto u : edges[v]) {
if(u.F != p) {
int val = dp[u.F] + u.S - max(dp[u.F] , gp[u.F]);
if(val > mx1) {
mx2 = mx1;
mx1 = val;
}
else if(val > mx2) {
mx2 = val;
}
}
}
for (auto u : edges[v]) {
if(u.F != p) {
int others = dp[v] - max(dp[u.F] , gp[u.F]);
int val = (mx1 == dp[u.F] + u.S - max(dp[u.F] , gp[u.F]) ? mx2 : mx1);
zp[v] = max(zp[v] , zp[u.F] + others);
zp[v] = max(zp[v] , zp[u.F] + u.S + others + val);
for (auto x : edges[u.F]) {
if(x.F != v) {
int u_others = dp[u.F] - max(dp[x.F] , gp[x.F]);
zp[v] = max(zp[v] , zp[x.F] + x.S + u.S + others + u_others);
}
}
}
}
}
int main() {
FAST;
cin >> n;
for (int i = 0; i < n - 1; ++i) {
int x , y , z; cin >> x >> y >> z;
x-- , y--;
edges[x].PB({y , z});
edges[y].PB({x , z});
}
dfs(0);
cout << zp[0] << '\n';
}
