#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<ctime>
#include<cstdlib>
#include<string>
#include<cmath>
using namespace std;
const int MOD=972327,step=11,mul=37327;
inline int read()
{
	int x=0;char ch=getchar();
	while(ch<'0'&&ch>'9'){ch=getchar();}
	while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
	return x;
}
int M,t1,t2,t,key,tot=0,temp1,temp2;
double ans=0;
inline double mymax(double xx,double yy)
{return xx<yy?yy:xx;}
struct Hash
{
	int id,v;
}H[1000000];
int find(int x)
{
	key=1LL*x*mul%MOD;
	while(H[key].id)
	{
		if(H[key].v==x)
			return H[key].id;
		key+=step;
		if(key>=MOD)
			key-=MOD;
	}
	return 0;
}
int insert(int x)
{
	key=1LL*x*mul%MOD;
	while(H[key].id)
	{
		key+=step;
		if(key>=MOD)
			key-=MOD;
	}
	H[key].id=++tot;
	H[key].v=x;
	return H[key].id;
}
int lin[200010],len=0,in_deg[200010];
struct edge
{
	int y,next,v;
	bool leaf_to_root;
}e[200010];
inline void insert(int xx,int yy,int vv)
{
	e[++len].next=lin[xx];
	lin[xx]=len;
	e[len].y=yy;
	e[len].v=vv;
	in_deg[yy]++;
}
int q[200010],head,tail,dis[200010];
bool vis[200010];
void bfs()
{
	head=0;tail=-1;
	for(int i=1;i<=tot;i++)
		if(in_deg[i]==1)
			q[++tail]=i,vis[i]=1;
	memset(in_deg,0,sizeof(in_deg));
	for(;head<=tail;head++)
	{
		for(int i=lin[q[head]];i;i=e[i].next)
		{
			if(!vis[e[i].y])
			{
				e[i].leaf_to_root=1;
				in_deg[e[i].y]++;
				q[++tail]=e[i].y;
			}
		}
	}
}
void top_sort()
{
	memset(dis,10,sizeof(dis));
	head=0,tail=-1;
	for(int i=1;i<=tot;i++)
		if(!in_deg[i])
			q[++tail]=i,dis[i]=0;
	for(;head<=tail;head++)
	{
		for(int i=lin[q[head]];i;i=e[i].next)
		{
			if(!e[i].leaf_to_root)
				continue;
			dis[e[i].y]=min(dis[e[i].y],dis[q[head]]+e[i].v);
			in_deg[e[i].y]--;
			if(!in_deg[e[i].y])
				q[++tail]=e[i].y;
		}
	}
	for(int i=1;i<=tot;i++)
	{
		ans=mymax(ans,dis[i]);
		for(int j=lin[i];j;j=e[j].next)
		{
			int tmp=e[j].v-abs(dis[e[j].y]-dis[i]);
			if(tmp>0)
				ans=max(ans,1.0*tmp/2+max(dis[e[j].y],dis[i]));
		}
	}
}
int main()
{
	freopen("firelead.in","r",stdin);
	freopen("firelead.out","w",stdout);
	M=read();
	for(int i=1;i<=M;i++)
	{
		t1=read(),t2=read(),t=read();
		temp1=find(t1),temp2=find(t2);
		if(temp1)
			t1=temp1;
		else
			t1=insert(t1);
		if(temp2)
			t2=temp2;
		else
			t2=insert(t2);
		insert(t1,t2,t),insert(t2,t1,t);
	}
	bfs();
	top_sort();
	printf("%.1lf\n",ans);
	fclose(stdin),fclose(stdout);
	return 0;
}