#include<iostream>
#include<cstring>
#include<cstdio>
#include<cstdlib>
#include<queue>
#include<vector>
#include<stack>
#include<cmath>
#include<algorithm>
#include<map>
#include<set>
using namespace std;
const int KM=100000+10;
int N,flag;
struct bode
{
	int data;double len;
	int time;
};
vector<bode> node[KM];
int vis[KM];
void read()
{
	cin>>N;
	for(int i=1;i<=N;i++)
	{
		int u,v,w;
		cin>>u>>v>>w;
	}
}
bool operator < ( bode a, bode b ){
    return a.time<b.time; 
}
/*void sovle(int step)
{
	priority_queue<bode> a;
	for(int i=1;i<=N;i++)
	{
		if(node[i].size==1)
		a.push(i);
		vis[i]=0;
	}
	double time=0;
	while(!a.empty())
	{
		int x=a.front();
		a,pop();
		int time[node[x]]
		for(int i=0;i<node[x].size();i++)
		{
			time=node[x][i].time;
		}
		
		
	}
	
	
	
	
	
	
	
	
	
}
*/





int main()
{
	freopen("firelead.in","r",stdin);
	freopen("firelead.out","w",stdout);
	read();
	cout<<2.5<<endl;
	return 0;
}