#include <bits/stdc++.h>
using namespace std;
const int maxn=60;
const double eps=1e-12;
#define IN inline
struct Point{
	double x,y,z;
	IN Point operator+(const Point &t)const{return {x+t.x,y+t.y,z+t.z};}
	IN Point operator-(const Point &t)const{return {x-t.x,y-t.y,z-t.z};}
	IN Point operator*(const Point &t)const{return {y*t.z-z*t.y,z*t.x-x*t.z,x*t.y-y*t.x};}
	IN Point operator*(const double &t)const{return{x*t,y*t,z*t};}
}a[maxn];
IN double sqr(double x){return x*x;}
IN double dis(Point a){return sqr(a.x)+sqr(a.y)+sqr(a.z);}

double ans=1e18;
void solve(){
	int n;
	cin>>n;
	for(int i=1;i<=n;++i){
		cin>>a[i].x>>a[i].y>>a[i].z;
	}
	for(int i=1;i<=n;++i){
		for(int j=i+1;j<=n;++j){
			for(int k=j+1;k<=n;++k){
				Point p=a[i],q=a[j],r=a[k];
				Point no=(p-q)*(r-p);
				double d=dis(no);
				if(d<eps)continue;
				double dd=0;
				int f1=0,f2=0;
				int ii=0;
				for(int m=1;m<=n;++m){
					Point mm=a[m];
					double h=(no.x*(mm.x-p.x)+no.y*(mm.y-p.y)+no.z*(mm.z-p.z))/sqrt(d);
					// if(h>ans){
					// 	cout<<i<<' '<<j<<' '<<k<<'\n';
					// 	cout<<no.x<<' '<<no.y<<' '<<no.z<<'\n';
					// 	cout<<m<<'\n';
					// 	ans=h;
					// 	cout<<ans<<'\n';
					// }
					if(h<0)f1=1;
					if(h>0)f2=1;
					if(dd<fabs(h)){
						dd=fabs(h);
						ii=m;
					}
				}
				if(f1*f2==0&&ans>dd){
					ans=min(ans,dd);
					// cout<<i<<' '<<j<<' '<<k<<'\n';
					// cout<<ii<<'\n';
					// cout<<no.x<<' '<<no.y<<' '<<no.z<<'\n';
					// cout<<ans<<'\n';
				}
			}
		}
	}
	cout<<fixed<<setprecision(15);
	cout<<ans<<'\n';
}
int main()
{
	ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
	//fstream in("in.txt",ios::in);cin.rdbuf(in.rdbuf());
	int T=1;
	while(T--)solve();
}