#include<bits/stdc++.h>
#define ll long long
#define lll __int128
#define db double
#define ld long double
#define pii pair<int,int>
#define fi first
#define se second
#define vi vector<int>
using namespace std;
namespace IO
{
const int SZ=1<<20;
char gchar()
{
static char buf[SZ];
static int i=SZ;
if(i==SZ)i=0,fread(buf,1,SZ,stdin);
return buf[i++];
}
void pchar(char c)
{
static char buf[SZ];
static int i=0;
if(c)buf[i++]=c;
if(!c||i==SZ)fwrite(buf,1,i,stdout),i=0;
}
void pstr(string s,char end='\n')
{
for(char c:s)pchar(c);
pchar(end);
}
template<typename T>void read(T &u)
{
u=0;int f=1;
static char c;
while((c=gchar())>'9'||c<'0')if(c=='-')f=-1;
u=c-'0';
while((c=gchar())>='0'&&c<='9')
u=(u<<1)+(u<<3)+(c^48);
u*=f;
}
template<typename T,typename ...Args>void read(T &u,Args&...args){read(u),read(args...);}
template<typename T>void i_write(T u)
{
if(u>9)i_write(u/10);
pchar(u%10+'0');
}
template<typename T>void write(T u,char end='\n')
{
if(u<0)pchar('-'),u=-u;
if(u>9)i_write(u/10);
pchar(u%10+'0');
pchar(end);
}
}
using IO::read;
using IO::write;
const int N=2e5+10;
const ll inf=1e18;
int n;
vector<pii>e[N];
int v1[N],v2[N];
ll mx1[N],mx2[N],vg[N],f[N][2],g[N][2],h[N][2];
void dfs1(int u,int fa)
{
mx1[u]=mx2[u]=-inf,v1[u]=v2[u]=0;
for(auto it:e[u])
{
int v=it.fi,w=it.se;
if(v==fa)continue;
vg[v]=w,dfs1(v,u),f[u][0]+=max(f[v][0],f[v][1]+w);
ll val=f[v][0]+w-max(f[v][0],f[v][1]+w);
if(mx1[u]<val)v2[u]=v1[u],mx2[u]=mx1[u],v1[u]=v,mx1[u]=val;
else if(mx2[u]<val)v2[u]=v,mx2[u]=val;
}
f[u][1]=f[u][0]+mx1[u];
}
void dfs2(int u,int fa)
{
for(auto it:e[u])
{
int v=it.fi,w=it.se;
if(v==fa)continue;
if(v1[u]==v)swap(mx1[u],mx2[u]),swap(v1[u],v2[u]);
h[u][0]=g[u][0]-max(f[v][0],f[v][1]+w),h[u][1]=h[u][0]+mx1[u];
if(u>1)h[u][1]=max(h[u][1],h[u][0]+h[fa][0]+vg[u]-max(h[fa][0],h[fa][1]+vg[u]));
g[v][0]=f[v][0]+max(h[u][0],h[u][1]+w);
if(mx1[u]<mx2[u])swap(mx1[u],mx2[u]),swap(v1[u],v2[u]);
dfs2(v,u);
}
}
int main()
{
read(n);
for(int i=1,x,y,z;i<n;i++)
read(x,y,z),e[x].push_back({y,z}),e[y].push_back({x,z});
dfs1(1,0),g[1][0]=f[1][0],dfs2(1,0);
ll ans=0;
for(int i=1;i<=n;i++)ans=max(ans,g[i][0]);
printf("%lld",ans);
return 0;
}
