#include<cstdio>
#include<algorithm>
#include<vector>
#include<cstring>
using namespace std;
int alln;
vector <pair<int,int> > E[200005];
int dp[200005][2][2];
int recur(int u,int ins,int wp,int pre){
if(dp[u][ins][wp] >= 0)
return dp[u][ins][wp];
if(ins == 1){
if(wp == 0 && E[u].size()-1 < 2)
return dp[u][ins][wp] = 0;
else if(wp == 1 && E[u].size()-1 < 1)
return dp[u][ins][wp] = 0;
}
int sum = 0;
for(int i=0;i<E[u].size();++i){
int v = E[u][i].first;
if(v == pre)
continue;
int w = E[u][i].second;
sum += max( recur(v,0,0,u) ,max(recur(v,1,0,u) , recur(v,1,1,u)+w*(E[v].size() > 1) ) );
}
if(ins == 0) /// || leaf
return dp[u][ins][wp] = sum;
int mx1,mx2;
mx1 = mx2 = 0;
for(int i=0;i<E[u].size();++i){
int v = E[u][i].first;
if(v == pre)
continue;
int w = E[u][i].second;
int del = max(dp[v][0][0] , max(dp[v][1][0] , dp[v][1][1]+w*(E[v].size() > 1) ) );
int add = max(dp[v][0][0] , dp[v][1][0]) + w;
int now = sum-del+add;
if( mx1 < now )
mx2 = mx1 , mx1 = now;
else if(mx2 < now)
mx2 = now;
}
if(wp == 1)
return dp[u][ins][wp] = mx1;
if(E[u].size() <= 2)
return dp[u][ins][wp] = 0;
return dp[u][ins][wp] = mx1+mx2-sum;
}
int main()
{
memset(dp,-1,sizeof(dp));
scanf("%d",&alln);
for(int i=1;i<alln;++i){
int u,v,w;
scanf("%d%d%d",&u,&v,&w);
E[u].push_back({v,w});
E[v].push_back({u,w});
}
printf("%d\n",max(recur(1,0,0,0) , recur(1,1,0,0) ) );
return 0;
}
/**
5
1 2 10
1 3 40
1 4 15
1 5 20
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
*/
