#include<bits/stdc++.h>
using namespace std;
#define _for(i,a,b) for(int i=(a);i<(b);++i)
#define rep(i,a,b) for(int i=(a);i<=(b);++i)
#define per(i,a,b) for(int i=(a);i>=(b);--i)
#define debug(a) cout<<#a<<a<<endl;
#define int long long
#define io_speed_up ios::sync_with_stdio(false),cin.tie(0),cout.tie(0)
typedef long long ll;
typedef unsigned long long u64;
typedef pair<int,int> pii;
typedef vector<int> vi;
const int N=55;
const double eps=1e-8;
int sgn(double x){
    return x<-eps?-1:x>eps;
}
struct point3{
    double x,y,z;
}e[N];
struct line3{
    point3 a,b;
};
struct plane3{
    point3 a,b,c;
};
point3 xmu(point3 u,point3 v){
    point3 ret;
    ret.x=u.y*v.z-v.y*u.z;
    ret.y=u.z*v.x-u.x*v.z;
    ret.z=u.x*v.y-u.y*v.x;
    return ret;
}
double dmu(point3 u,point3 v){
    return u.x*v.x+u.y*v.y+u.z*v.z;
}
point3 subt(point3 u,point3 v){
    point3 ret;
    ret.x=u.x-v.x;
    ret.y=u.y-v.y;
    ret.z=u.z-v.z;
    return ret;
}
double vlen(point3 p){
    return sqrt(p.x*p.x+p.y*p.y+p.z*p.z);
}
point3 pvec(point3 s1,point3 s2,point3 s3){
    return xmu(subt(s1,s2),subt(s2,s3));
}
int dot_inline(point3 p1,point3 p2,point3 p3){
    return vlen(xmu(subt(p1,p2),subt(p2,p3)))<eps;
}
//tongce
int same_side(point3 p1,point3 p2,point3 s1,point3 s2,point3 s3){
    return dmu(pvec(s1,s2,s3),subt(p1,s1))*dmu(pvec(s1,s2,s3),subt(p2,s1))>eps;
}
int opp_side(point3 p1,point3 p2,point3 s1,point3 s2,point3 s3){
    return dmu(pvec(s1,s2,s3),subt(p1,s1))*dmu(pvec(s1,s2,s3),subt(p2,s1))<-eps;
}
double ptoplane(point3 p,point3 s1,point3 s2,point3 s3){
    return fabs(dmu(pvec(s1,s2,s3),subt(p,s1)))/vlen(pvec(s1,s2,s3));
}
int dot_onplane(point3 a,point3 b,point3 c,point3 d){
    return sgn(dmu(pvec(a,b,c),subt(d,a)));
}

void solve(){
    int n;
    cin>>n;
    for(int i=1;i<=n;i++){
        double x,y,z;
        cin>>x>>y>>z;
        e[i].x=x;
        e[i].y=y;
        e[i].z=z;
    }
    double ans=0x3f3f3f3f3f3f*1.0;
    for(int i=1;i<=n;i++){
        for(int j=i+1;j<=n;j++){
            for(int k=j+1;k<=n;k++){
                if(dot_inline(e[i],e[j],e[k])) continue;
                else{   
                    //cout<<i<<" "<<j<<" "<<k<<endl;
                    double temp=ptoplane(e[1],e[i],e[j],e[k]);
                    bool flag=0;
                    int tempp=1;
                    for(int p=2;p<=n;p++){
                        int flagt=dot_onplane(e[p],e[i],e[j],e[k]);
                        if(flagt==0) {
                            continue;
                        } 
                        else{
                            int flag2=opp_side(e[p],e[tempp],e[i],e[j],e[k]);                        
                            if(flag2==1){
                                //cout<<"yimian"<<p<<endl;
                                flag=1;
                            }
                            temp=max(temp,ptoplane(e[p],e[i],e[j],e[k]));
                            tempp=p;
                        }
                    }
                    if(flag==0){
                        ans=min(ans,temp);
                        //cout<<ans<<endl;
                    }
                }
                
            }
        }
    }
    cout<<fixed<<setprecision(15)<<ans<<endl;
}
signed main(){
    io_speed_up;
    solve();
    return 0;
}