#include<cstdio>
#include<queue>
#include<vector>
#include<algorithm>
#include<cstring>
#define inf (int)1e9
using namespace std;
const int maxn=100010;
int m,n,a[maxn],b[maxn],c[maxn],dis[maxn],vis[maxn],indegree[maxn];
struct poi{int u,w;};
vector<poi>s[maxn];
queue<int>q;
void Init(){
	for(int i=1;i<=m+1;i++)dis[i]=inf;
}
void Spfa(){//dis[i]表示燃烧到结点i所用的最短时间(距离)
	while(!q.empty()){
		int u=q.front();q.pop();
		vis[u]=0;
		for(int i=0;i<(int)s[u].size();i++){
			int v=s[u][i].u,w=s[u][i].w;
			if(dis[v]>dis[u]+w){
				dis[v]=dis[u]+w;
				if(!vis[v]){
					vis[v]=1,q.push(v);
				}
			}
		}
	}
}
int main(){
	freopen("firelead.in","r",stdin);
	freopen("firelead.out","w",stdout);
	scanf("%d",&m);
	int u,v,len;
	for(int i=1;i<=m;i++){
		scanf("%d%d%d",&u,&v,&len);
		s[u].push_back((poi){v,len}),s[v].push_back((poi){u,len});
		a[i]=u,b[i]=v,c[i]=len;
		indegree[v]++,indegree[u]++;
	}
	Init();
	for(int i=1;i<=m+1;i++){
		if(indegree[i]==1)dis[i]=0,q.push(i);//找到叶子节点
	}
	Spfa();
	double ans=0;
	for(int i=1;i<=m;i++)ans=max(ans,double(dis[a[i]]+dis[b[i]]+c[i])/2.0);
	printf("%.1lf\n",ans);
	return 0;
}