#include <iostream>
#include <cmath>

using namespace std;

const int N = 55;

struct Point
{
    int x, y, z;
    Point operator - (Point a)
    {
        return { x - a.x, y - a.y, z - a.z };
    }
    Point operator * (Point a)
    {
        return { y * a.z - z * a.y, z * a.x - x * a.z, x * a.y - y * a.x };
    }
    int operator & (Point a)
    {
        return x * a.x + y * a.y + z * a.z;
    }
}p[N];

double len(Point a)
{
    return sqrt(a.x * a.x + a.y * a.y + a.z * a.z);
}

int main()
{
    int n;
    cin >> n;

    for(int i = 1; i <= n; i ++)
        cin >> p[i].x >> p[i].y >> p[i].z;

    int cnt = 0;
    double ans = 1e18;
    for(int i = 1; i <= n; i ++)
        for(int j = i + 1; j <= n; j ++)
            for(int k = j + 1; k <= n; k ++)
                for(int t = k + 1; t <= n; t ++)
                {
                    Point p1 = p[j] - p[i], p2 = p[t] - p[k], v = p1 * p2;
                    if(!v.x && !v.y && !v.z)    continue;

                    double mi = 1e18, mx = -1e18;
                    for(int x = 1; x <= n; x ++)
                    {
                        double l = (p[x] & v) / len(v);
                        mi = min(mi, l), mx = max(mx, l);
                    }

                    ans = min(ans, mx - mi);
                }

    printf("%.11lf", ans);

    return 0;
}