#include<bits/stdc++.h>
#define lf double
#define ll long long
#define cc pair<char,char>
#define ull unsigned ll
#define ii pair<int,int>
#define li pair<ll,int>
#define iii pair<int,ii>
#define iiii pair<ii,ii>
#define iiii2 pair<int,iii>
#define lii pair<ll,ii>
#define lolo pair<ll,ll>
#define heap priority_queue
#define mp make_pair
#define st first
#define nd second
#define pb push_back
#define pf push_front
#define ppb pop_back
#define ppf pop_front
#define all(x) x.begin(),x.end()
#define len(x) strlen(x)
#define sz(x) (int) x.size()
#define orta ((bas+son)/2)
#define min3(x,y,z) min(min(x,y),z)
#define max3(x,y,z) max(max(x,y),z)
#define umin(x,y) x=min(x,y)
#define umax(x,y) x=max(x,y)
#define dbgs(x) cerr<<(#x)<<" --> "<<(x)<<" "
#define dbg(x) cerr<<(#x)<<" --> "<<(x)<<endl;getchar()
#define MOD 1000000000
#define inf 2000000005
#define N 100005
#define LOG 20
#define magic 100
#define KOK 250
#define EPS 0.0025
#define pw(x) (1<<(x))
#define PI 3.1415926535
using namespace std;
int n,x,y,z;
int dp[N][2];
vector<ii> v[N];
int pre[N];
void dfs(int node,int ata,int ue) {
for(int i=0;i<sz(v[node]);i++) {
ii go=v[node][i];
if(go.st==ata) {
swap(v[node][i],v[node][sz(v[node])-1]);
v[node].ppb();
i--;
continue ;
}
dfs(go.st,node,go.nd);
}
for(int i=0;i<sz(v[node]);i++) {
ii go=v[node][i];
pre[i+1]=pre[i]+dp[go.st][0];
}
// make center
int mx=-inf;
for(int i=0;i<sz(v[node]);i++) {
ii go=v[node][i];
for(int j=0;j<2;j++) {
umax(dp[node][j],pre[sz(v[node])]-dp[go.st][0]+go.nd+dp[go.st][1]+mx);
}
umax(mx,go.nd-dp[go.st][0]+dp[go.st][1]);
}
// not blocked
for(int i=0;i<sz(v[node]);i++) {
ii go=v[node][i];
umax(dp[node][0],dp[go.st][1]+go.nd+ue+pre[sz(v[node])]-dp[go.st][0]);
}
// no center
for(int j=0;j<2;j++) {
umax(dp[node][j],pre[sz(v[node])]);
}
//printf("node--> %d zero--> %d one--> %d\n",node,dp[node][0],dp[node][1]);
}
int main() {
#if 0
freopen("input.txt","r",stdin);
#endif
scanf("%d",&n);
for(int i=1;i<n;i++) {
scanf("%d %d %d",&x,&y,&z);
v[x].pb({y,z});
v[y].pb({x,z});
}
dfs(1,0,0);
printf("%d",dp[1][1]);
}
