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#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,n) for (int i=a;i<n;i++)
#define per(i,a,n) for (int i=n-1;i>=a;i--)
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
typedef vector<int> VI;
typedef long long ll;
typedef pair<int,int> PII;
typedef double db;
const ll mod=1000000007;

mt19937 mrand(chrono::high_resolution_clock::now().time_since_epoch().count());
int rnd(int x) { return mrand() % x;}

ll powmod(ll a,ll b) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;}
// head

ll inf=1ll<<60;
int T=1000;
const int N=201000;

int n;
vector<PII> e[N];
ll dp[N][4],ff[10100][2],gg[10100][2];

void dfs(int u,int f) {
	vector<array<ll,4>> px;
	for (auto p:e[u]) if (p.fi!=f) {
		int v=p.fi;
		dfs(v,u);
		ll p1=dp[v][0]+p.se,p2=dp[v][1]+p.se,p3=dp[v][2]+p.se,p0=max(dp[v][3]+p.se,dp[v][0]);
		px.pb({p0,p1,p2,p3});
	}
	int tt=max(min(T,SZ(px)/2+1),1);
	shuffle(all(px),mrand);
	for (int i=0;i<=2*tt;i++) ff[i][0]=ff[i][1]=-inf; ff[tt][0]=0;
	for (auto p:px) {
		for (int i=0;i<=2*tt;i++) rep(j,0,2) gg[i][j]=ff[i][j],ff[i][j]=gg[i][j]+p[0];
		rep(i,0,2*tt) rep(j,0,2) ff[i][j]=max(ff[i][j],gg[i+1][j]+p[1]);
		rep(i,0,2*tt) rep(j,0,2) ff[i+1][j]=max(ff[i+1][j],gg[i][j]+p[3]);
		rep(i,0,2*tt+1) rep(j,0,2) ff[i][j^1]=max(ff[i][j^1],gg[i][j]+p[2]);
	}
	dp[u][0]=ff[tt][0]; dp[u][1]=ff[tt-1][0]; dp[u][3]=ff[tt+1][0]; dp[u][2]=ff[tt][1];
	//printf("%d %lld %lld %lld\n",u,dp[u][0],dp[u][1],dp[u][2]);
}
int main() {
	scanf("%d",&n);
	rep(i,1,n) {
		int u,v,w;
		scanf("%d%d%d",&u,&v,&w);
		e[u].pb({v,w});
		e[v].pb({u,w});
	}
	dfs(1,0);
	printf("%lld\n",dp[1][0]);
}