#include <bits/stdc++.h>
using namespace std;

//Start
typedef long long ll;
typedef double db;
#define mp(a,b) make_pair(a,b)
#define x first
#define y second
#define be(a) a.begin()
#define en(a) a.end()
#define sz(a) int((a).size())
#define pb(a) push_back(a)
const int inf=0x3f3f3f3f;
const ll INF=0x3f3f3f3f3f3f3f3f;

//Data
const int N=2000;
const db eps=1e-12;
int n,m;

//Convex
mt19937 orz(time(0));
db reps(){return (1.*(orz()%98)/97-.5)*eps;}
struct point{
	db x,y,z;
	void shake(){x+=reps(),y+=reps(),z+=reps();}
	db len(){return sqrt(x*x+y*y+z*z);}
	point operator-(point p){return (point){x-p.x,y-p.y,z-p.z};}
	point operator*(point p){return (point){y*p.z-p.y*z,z*p.x-p.z*x,x*p.y-p.x*y};}
	db operator^(point p){return x*p.x+y*p.y+z*p.z;} 
}a[N];
struct plane{
	int v[3];
	point flag(){return (a[v[1]]-a[v[0]])*(a[v[2]]-a[v[0]]);}
	db area(){return flag().len()/2;}
	int see(point p){return ((p-a[v[0]])^flag())>0;}
}f[N],g[N];
int vis[N][N]; 
void Convex(){
	#define ft f[j].v[t]
	#define bk f[j].v[(t+1)%3]
	f[m++]=(plane){0,1,2},f[m++]=(plane){2,1,0};
	for(int i=3;i<n;i++){
		int cnt=0,b;
		for(int j=0;j<m;j++){
			if(!(b=f[j].see(a[i]))) g[cnt++]=f[j];
			for(int t=0;t<3;t++) vis[ft][bk]=b;
		}
		for(int j=0;j<m;j++)
			for(int t=0;t<3;t++)
				if(vis[ft][bk]&&!vis[bk][ft]) g[cnt++]=(plane){ft,bk,i};
		m=cnt;
		for(int j=0;j<m;j++) f[j]=g[j];
	}
} 

//Main
int main(){
	ios::sync_with_stdio(0);
	cin.tie(0),cout.tie(0);
	cin>>n;
	for(int i=0;i<n;i++) cin>>a[i].x>>a[i].y>>a[i].z,a[i].shake();
	Convex(); 
	double ans=1e9;
	for(int i=0;i<m;i++){
		double mx=0;
		for(int j=0;j<n;++j) mx=max(mx,fabs(((a[j]-a[f[i].v[0]])^f[i].flag())/f[i].flag().len()));
		ans=min(ans,mx);
	}
	printf("%.12lf\n",ans);
	return 0;
}