#include <stdio.h>
#include <string.h>

#include <cmath>
#include <algorithm>

#define LOG(FMT...) fprintf(stderr, FMT)

using namespace std;

typedef long long LL;
typedef long double LDB;
constexpr int N = 1000005;

int n;
struct Vec {
	LL x, y, z;
	Vec operator - (const Vec &t) const {
		return (Vec){x - t.x, y - t.y, z - t.z};
	}
	Vec operator * (const Vec &t) const {
		return (Vec){y * t.z - z * t.y, x * t.z - z * t.x, x * t.y - y * t.x};
	}
	LL operator & (const Vec &t) const {
		return x * t.x + y * t.y + z * t.z;
	}
	LDB md() const {
		return sqrtl(x * x + y * y + z * z);
	}
} w[N];
LDB res = 1e36;

int main() {
	scanf("%d", &n);
	for (int i = 0; i < n; ++i) {
		scanf("%d%d%d", &w[i].x, &w[i].y, &w[i].z);
	}
	for (int k = 0; k < n; ++k) {
		LL maxv = 0;
		auto chk = [&](const Vec &t) {
			for (int i = 0; i < n; ++i) {
				LL v = (w[i] - w[k]) & t;
				if (v < 0) {
					return false;
				}
				if (v > maxv) {
					maxv = v;
				}
			}
			return true;
		};
		for (int i = k + 1; i < n; ++i) {
			for (int j = k + 1; j < n; ++j) {
				if (i == j) {
					continue;
				}
				Vec m = (w[i] - w[k]) * (w[j] - w[k]);
				if (!chk(m)) {
					continue;
				}
				res = min(res, maxv / m.md());
			}
		}
	}
	printf("%.15Lf\n", res);
	return 0;
}