// g++-13 3.cpp -std=c++17 -O2 -I .
#include <bits/stdc++.h>
using namespace std;

using ll = long long;
using ld = long double;
 
using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using vld = vector<ld>;
using vvld = vector<vld>;
using vst = vector<string>;
using vvst = vector<vst>;
 
#define fi first
#define se second
#define pb push_back
#define eb emplace_back
#define pq_big(T) priority_queue<T,vector<T>,less<T>>
#define pq_small(T) priority_queue<T,vector<T>,greater<T>>
#define all(a) a.begin(),a.end()
#define rep(i,start,end) for(ll i=start;i<(ll)(end);i++)
#define per(i,start,end) for(ll i=start;i>=(ll)(end);i--)
#define uniq(a) sort(all(a));a.erase(unique(all(a)),a.end())

using T = tuple<ld,ld,ld>;

ld g(int n,vector<T> &points,ld val1,ld val2){
  ld val3=sqrt(1-val1*val1-val2*val2);
  ld mx=-1e9,mn=1e9;
  
  rep(i,0,n){
    auto [x,y,z]=points[i];
    ld val=val1*x+val2*y+val3*z;
    mx=max(mx,val);
    mn=min(mn,val);
  }

  return mx-mn;
}

ld f(int n,vector<T> &points,ld val){
  ld t=1-val*val;
  
  ld low=sqrt(t),high=sqrt(t);
  low*=-1;

  rep(time,0,500){
    ld mid1 = (low * 2.0L + high) / 3.0L;
    ld mid2 = (low + high * 2.0L) / 3.0L;

    if(g(n,points,val,mid1)<g(n,points,val,mid2)){
      high=mid2;
    }
    else{
      low=mid1;
    }
  }

  return g(n,points,val,low);
}

ld solve(int n,vector<T> &points){
  ld low=-1,high=1;
  rep(time,0,500){
    ld mid1 = (low * 2.0L + high) / 3.0L;
    ld mid2 = (low + high * 2.0L) / 3.0L;

    if(f(n,points,mid1)<f(n,points,mid2)){
      high=mid2;
    }
    else{
      low=mid1;
    }
  }

  // cout<<low<<endl;
  return f(n,points,low);
}

int main(){
  ios::sync_with_stdio(false);
  cin.tie(nullptr);

  int n;cin>>n;
  vector<T> points(n);
  
  rep(i,0,n){
    int x,y,z;cin>>x>>y>>z;
    points[i]={x,y,z};
  }

  ld ans=1e9;
  vector<T> points2(n);

  rep(i,0,6){
    rep(j,0,n){
      auto [x,y,z]=points[j];
      if(i==0)points2[j]={x,y,z};
      if(i==1)points2[j]={x,z,y};
      if(i==2)points2[j]={y,x,z};
      if(i==3)points2[j]={y,z,x};
      if(i==4)points2[j]={z,x,y};
      if(i==5)points2[j]={z,y,x};

      auto [x2,y2,z2]=points2[j];
      // cout<<x2<<" "<<y2<<" "<<z2<<endl;
    }

    ans=min(ans,solve(n,points2));
    // cout<<ans<<endl;
  }

  cout<<fixed<<setprecision(20);
  cout<<ans<<endl;
}