#include<bits/stdc++.h>
#define v e[i].to
using namespace std;
int m,fi[100005],tot,f[100005],ma=-1,fa[100005],in[100005];
struct edge{
	int to,next,cost;
}e[200005];
void edge_add(int x,int y,int z){
	e[++tot].cost=z;
	e[tot].next=fi[x];
	e[tot].to=y;
	fi[x]=tot;
}
void dfs(int x){
	int tem1=0,tem2=0;
	for(int i=fi[x];i;i=e[i].next){
		if(fa[x]==v)continue;
		fa[v]=x;
		dfs(v);
		if(f[v]+e[i].cost<f[x]){
			f[x]=f[v]+e[i].cost;
		}
	}
	for(int i=fi[x];i;i=e[i].next){
		if(v==fa[x])continue;
		if(f[v]+e[i].cost>tem1){
			tem1=f[v]+e[i].cost;
			tem2=v;
		}
	}
	int tem3=0;
	for(int i=fi[x];i;i=e[i].next){
		if(v==fa[x])continue;
		if(tem2==v)continue;
		tem3=max(tem3,f[v]+e[i].cost);
	}
	ma=max(ma,tem1+tem3);
}
int main()
{
	freopen("firelead.in","r",stdin);
	freopen("firelead.out","w",stdout);
//	freopen("1.txt","r",stdin);
	scanf("%d",&m);
	for(int i=1;i<=m;i++){
		int u,V,len;
		scanf("%d%d%d",&u,&V,&len);
		edge_add(u,V,len);
		edge_add(V,u,len);
		in[u]++;
		in[V]++;
	}
	memset(f,0x3f,sizeof(f));
	for(int i=1;i<=m+1;i++)
	if(in[i]==1)f[i]=0;
	dfs(1);
	printf("%.1f",(double)ma/(double)2);
	return 0;
}