/** gnu specific **/
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
/** contains everything I need in std **/
#include <bits/stdc++.h>

#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(S) ((int)S.size())
#define FOR(i, st_, n) for(int i = st_; i < n; ++i)
#define RFOR(i, n, end_) for(int i = (n)-1; i >= end_; --i)
#define x first
#define y second
#define pb push_back
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
typedef pair<double, double> pdd;
typedef unsigned long long ull;
typedef long double LD;
typedef pair<ull, ull> pull;
using namespace __gnu_pbds;
typedef tree<ll, null_type, less<>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
using namespace std;
#ifdef ONPC
mt19937 rnd(228);
#else
mt19937 rnd(chrono::high_resolution_clock::now().time_since_epoch().count());
#endif


struct Point {
    double x, y;
};

double dist(const Point& a, const Point& b) {
    return sqrt((a.x - b.x) * (a.x - b.x) + (a.y - b.y) * (a.y - b.y));
}

struct Circle {
    Point center;
    double radius;

    bool contains(const Point& p) const {
        return dist(center, p) <= radius + 1e-9;
    }
};

// Circle from two points
Circle make_circle_two_points(const Point& p1, const Point& p2) {
    Point center = {(p1.x + p2.x) / 2.0, (p1.y + p2.y) / 2.0};
    double radius = dist(p1, center);
    return {center, radius};
}

// Circle from three points
Circle make_circle_three_points(const Point& p1, const Point& p2, const Point& p3) {
    double A = p2.x - p1.x, B = p2.y - p1.y;
    double C = p3.x - p1.x, D = p3.y - p1.y;
    double E = A * (p1.x + p2.x) + B * (p1.y + p2.y);
    double F = C * (p1.x + p3.x) + D * (p1.y + p3.y);
    double G = 2 * (A * (p3.y - p2.y) - B * (p3.x - p2.x));

    if (fabs(G) < 1e-9) return {{0, 0}, numeric_limits<double>::max()}; // Collinear points

    Point center = {(D * E - B * F) / G, (A * F - C * E) / G};
    double radius = dist(center, p1);
    return {center, radius};
}

// Welzl's algorithm
Circle welzl(vector<Point>::iterator it, vector<Point>::iterator end, vector<Point> R) {
    if (it == end || R.size() == 3) {
        if (R.empty()) return {{0, 0}, 0};
        if (R.size() == 1) return {R[0], 0};
        if (R.size() == 2) return make_circle_two_points(R[0], R[1]);
        return make_circle_three_points(R[0], R[1], R[2]);
    }

    Point p = *it;
    Circle c = welzl(it + 1, end, R);
    if (c.contains(p)) return c;

    R.push_back(p);
    return welzl(it + 1, end, R);
}

Circle min_enclosing_circle(vector<Point>& points) {
    random_shuffle(points.begin(), points.end());
    return welzl(points.begin(), points.end(), {});
}
int solve()
{
	int n;
	if(!(cin>>n))return 1;
	vector<array<double,3>> A(n);
	FOR(i,0,n)FOR(j,0,3)cin>>A[i][j];
	shuffle(all(A),rnd);
    vector<Point> p1(n), p2(n), p3(n);
    FOR(i,0,n)p1[i]={A[i][0],A[i][1]};
    FOR(i,0,n)p2[i]={A[i][0],A[i][2]};
    FOR(i,0,n)p3[i]={A[i][1],A[i][2]};
    

    Circle c1 = min_enclosing_circle(p1);
    Circle c2 = min_enclosing_circle(p2);
    Circle c3 = min_enclosing_circle(p3);
	double res =min(c1.radius,min(c2.radius,c3.radius));
	cout << fixed << setprecision(10) << 2*res << '\n';
    return 0;
}

int32_t main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    int TET = 1e9;
    //cin >> TET;
    for (int i = 1; i <= TET; i++)
    {
        if (solve())
        {
            break;
        }
#ifdef ONPC
        cout << "__________________________" << endl;
#endif
    }
#ifdef ONPC
    cerr << endl << "finished in " << clock() * 1.0 / CLOCKS_PER_SEC << " sec" << endl;
#endif
}