#include <bits/stdc++.h>
using namespace std;
#define sz(v) (int)(v).size()
#define all(v) (v).begin(), (v).end()
void solve()
{
int n; cin >> n;
vector<vector<pair<int,int>>> adj(n + 1);
for(int i = 0; i < n - 1; i++){
int u,v,c; cin >> u >> v >> c;
adj[u].emplace_back(v, c);
adj[v].emplace_back(u, c);
}
vector<vector<int>> dp(n + 1, vector<int>(2, 0)), sdp(n + 1, vector<int>());
const int inf = 2e9;
function<void(int,int)> calc_dp = [&](int x, int p) -> void{
for(int i = 0; i < 2; i++) sdp[x].push_back(-inf);
for(auto [v, w] : adj[x])if(v != p){
calc_dp(v, x);
dp[x][0] = dp[x][0] + max(dp[v][1] + w, dp[v][0]);
sdp[x].push_back(-max(dp[v][1] + w, dp[v][0]) + (dp[v][0] + w));
}
sort(all(sdp[x]), greater<int>());
dp[x][1] = dp[x][0] + sdp[x][0];
};
calc_dp(1, -1);
int answer = 0;
function<void(int,int)> reroot = [&](int x, int p) -> void{
answer = max(answer, dp[x][0]);
for(auto [v, w] : adj[x])if(v != p){
int ndp0 = dp[x][0] - max(dp[v][1] + w, dp[v][0]);
int ndp1 = ndp0;
int sdpv = -max(dp[v][1] + w, dp[v][0]) + (dp[v][0] + w);
if(sdp[x][0] != sdpv){
ndp1 = ndp0 + sdp[x][0];
}
else ndp1 = ndp0 + sdp[x][1];
dp[v][0] = dp[v][0] + max(ndp1 + w, ndp0);
sdp[v].push_back(-max(ndp1 + w, ndp0) + (ndp0 + w));
sort(all(sdp[v]), greater<int>());
dp[v][1] = dp[v][0] + sdp[v][0];
reroot(v, x);
}
};
reroot(1, -1);
cout << answer << "\n";
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
#define name "InvMOD"
if(fopen(name".INP", "r")){
freopen(name".INP","r",stdin);
freopen(name".OUT","w",stdout);
}
int t = 1; //cin >> t;
while(t--) solve();
return 0;
}
