#include <bits/stdc++.h>
using namespace std;
const long long INF = 1000000000000000000;
struct point{
  long long x, y, z;
  point(){
  }
  point(long long x, long long y, long long z): x(x), y(y), z(z){
  }
  point operator -(point P){
    return point(x - P.x, y - P.y, z - P.z);
  }
};
double abs(point P){
  return hypot(P.x, P.y, P.z);
}
long long dot(point P, point Q){
  return P.x * Q.x + P.y * Q.y + P.z * Q.z;
}
point cross(point P, point Q){
  return point(P.y * Q.z - P.z * Q.y, P.z * Q.x - P.x * Q.z, P.x * Q.y - P.y * Q.x);
}
int main(){
  cout << fixed << setprecision(20);
  int n;
  cin >> n;
  vector<point> P(n);
  for (int i = 0; i < n; i++){
    cin >> P[i].x >> P[i].y >> P[i].z;
  }
  vector<point> C;
  for (int i = 0; i < n; i++){
    for (int j = i + 1; j < n; j++){
      C.push_back(P[j] - P[i]);
    }
  }
  int cnt = C.size();
  for (int i = 0; i < cnt; i++){
    for (int j = i + 1; j < cnt; j++){
      point tmp = cross(C[i], C[j]);
      if (abs(tmp) != 0){
        C.push_back(tmp);
      }
    }
  }
  cnt = C.size();
  double ans = INF;
  for (int i = 0; i < cnt; i++){
    long long mn = INF, mx = -INF;
    for (int j = 0; j < n; j++){
      long long x = dot(C[i], P[j]);
      mn = min(mn, x);
      mx = max(mx, x);
    }
    ans = min(ans, (mx - mn) / abs(C[i]));
  }
  cout << ans << endl;
}