#include <bits/stdc++.h>
using namespace std;
struct edge{
int v,w;
edge(int v=0,int w=0): v(v), w(w) {}
};
int n;
vector <edge> G[200005];
int dp[200005][5];
inline int val1(int pos,int w){
return dp[pos][0] + w;
}
inline int val02(int pos,int w){
return max(dp[pos][0], dp[pos][2] + w);
}
void dfs(int u,int p){
for(int i=0;i<G[u].size();i++){
int v = G[u][i].v;
if (v == p) continue;
dfs(v,u);
}
// dp[i][0]
for(int i=0;i<G[u].size();i++){
int v = G[u][i].v;
if (v == p) continue;
dp[u][0] += val02(v,G[u][i].w);
}
// dp[i][1]
int fi02=0,se02=0,fiva02=0, seva02=0;
for(int i=0;i<G[u].size();i++){
int v = G[u][i].v;
int w = G[u][i].w;
if (v == p) continue;
if (!fi02 || val1(v,w) - val02(v,w) >= val1(fi02,fiva02) - val02(fi02,fiva02))
se02 = fi02,
seva02 = fiva02,
fi02 = v,
fiva02 = w;
else if (!se02 || val1(v,w) - val02(v,w) >= val1(se02,seva02) - val02(se02,seva02))
se02 = v,
seva02 = w;
}
dp[u][1] = - (int) 1e9;
if ((int)G[u].size() - (u != 1) > 1){
//cout << "u " << u << ' ' << fi02 << ' ' << se02 << endl;
dp[u][1] = dp[u][0] - val02(fi02,fiva02) - val02(se02,seva02) + val1(fi02,fiva02) + val1(se02,seva02);
for(int i=0;i<G[u].size();i++){
int v = G[u][i].v;
int w = G[u][i].w;
if (v == p) continue;
if (v != fi02)
dp[u][1] = max(dp[u][1], dp[u][0] - val02(fi02,fiva02) + val1(fi02,fiva02) - val02(v,w) + w + dp[v][1]);
else
dp[u][1] = max(dp[u][1], dp[u][0] - val02(se02,seva02) + val1(se02,seva02) - val02(v,w) + w + dp[v][1]);
}
}
// dp[i][2]
dp[u][2] = -(int)1e9;
for(int i=0;i<G[u].size();i++){
int v = G[u][i].v;
int w = G[u][i].w;
if (v == p) continue;
dp[u][2] = max(dp[u][2], dp[u][0] - max(dp[v][0], dp[v][2] + G[u][i].w) + dp[v][0] + G[u][i].w);
}
}
int main(){
scanf("%d",&n);
for(int i=1;i<n;i++){
int x,y,w;
scanf("%d %d %d",&x,&y,&w);
G[x].push_back(edge(y,w));
G[y].push_back(edge(x,w));
}
dfs(1,1);
cout << max(dp[1][0], dp[1][1]) << endl;
//for(int i=1;i<=n;i++)
// cout << "I " << i << ' ' << dp[i][0] <<' ' << dp[i][1] << ' ' << dp[i][2] << endl;
}
/*
10
4 10 2
1 2 21
1 3 13
6 7 1
7 9 5
2 4 3
2 5 8
1 6 55
6 8 34
*/
