#define _CRT_SECURE_NO_WARNINGS
#define REL

#pragma GCC optimize("Ofast")

#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <deque>
#include <queue>
#include <iomanip>
#include <cstdio>
#include <unordered_map>
#include <unordered_set>
#include <map>
#include <string>
#include <set>
#include <bitset>
#include <cstdint>
#include <cstring>
#include <random>
#include <cassert>
#include <complex>

using namespace std;

typedef int64_t i64;
typedef long long LL;
typedef long double LD;
typedef unsigned int uint;
typedef complex <LD> cld;
typedef complex <double> cd;
typedef unsigned long long ULL;

#define endl "\n"
#define dendl "\n\n"
#define mp make_pair
#define size(v) (int)v.size()
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()

/////////////////////////////////////////////////////////////////////

template <typename T>
T sqr(T a) {
	return a * a;
}

template <typename T>
int sign(T a) {
	if (a == 0)
		return 0;
	return (a > 0 ? 1 : -1);
}

template <typename T1, typename T2>
T2 sum_mod(T1 x, T2 MOD) {
	if (x < 0)
		x += MOD;
	if (x >= MOD)
		x -= MOD;
	return x;
}

template <typename T1, typename T2>
T2 mul_mod(T1 x, T2 MOD) {
	if (x < 0)
		return (abs(x) % MOD == 0 ? 0 : MOD - abs(x) % MOD);
	return x % MOD;
}

template <typename T>
bool uax(T& a, const T b) {
	if (a < b) {
		a = b;
		return true;
	}
	return false;
}

template <typename T>
bool uin(T& a, const T b) {
	if (a > b) {
		a = b;
		return true;
	}
	return false;
}

template <typename T1, typename T2>
istream& operator >> (istream& in, pair<T1, T2>& p) {
	in >> p.first >> p.second;
	return in;
}

template <typename T1, typename T2>
ostream& operator << (ostream& out, pair<T1, T2>& p) {
	out << p.first << ' ' << p.second;
	return out;
}

mt19937_64 gen_rand;

const int N = (int)2e5 + 7;
const int LOG = 20;
const int N_ = (int)8e2 + 7;
const int MAXN = (int)2e6 + 7;
const int MOD = (int)1e9 + 7;
const int INF = (int)2e9 + 7;
const int CONST = 300;
const LL LINF = (i64)2e15;
const LD PI = 3.1415926535897932384626433832795;
const LD EPS = 1e-6;

/////////////////////////////////////////////////////////////////////

struct Point {
	LD x, y;
	Point() {};
	Point(LD x, LD y) :
		x(x), y(y) {};
};

Point turn(const Point& a) {
	return Point(-a.y, a.x);
}

Point operator * (const Point& a, LD x) {
	return Point(a.x * x, a.y * x);
}

Point operator - (const Point& a, const Point& b) {
	return Point(a.x - b.x, a.y - b.y);
}

Point operator + (const Point& a, const Point& b) {
	return Point(a.x + b.x, a.y + b.y);
}

LD operator * (const Point& a, const Point& b) {
	return a.x * b.y - b.x * a.y;
}

Point mid(const Point& a, const Point& b) {
	return Point((a.x + b.x) / 2, (a.y + b.y) / 2);
}

int n;
Point p[N];

LD 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));
}

bool check(const Point& cen, LD d) {
	for (int i = 0; i < n; i++) {
		if (dist(p[i], cen) - d < EPS)
			continue;
		return false;
	}
	return true;
}

struct Line {
	Point a, b;
	Line() {};
	Line(const Point& a, const Point& b) :
		a(a), b(b) {};
};

Point inter(const Line& a, const Line& b) {
	LD t = ((a.a - b.a) * (a.a - a.b)) / ((b.a - b.b) * (a.a - a.b));
	return b.a + (b.a - b.b) * t;
}

int main() {
	double start = clock();
#ifdef _DEBUG
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);
	cout << fixed << setprecision(20);
	cerr << fixed << setprecision(20);
	gen_rand.seed(0);
#else
	cout << fixed << setprecision(20);
	ios_base::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);
	gen_rand.seed(time(0));
#endif

	cin >> n;
	LD x = 0, y = 0;
	for (int i = 0; i < n; i++) {
		cin >> p[i].x >> p[i].y;
		x += p[i].x, y += p[i].y;
	}

	x /= n, y /= n;
	LD shift = 0.1;
	for (int i = 0; i < 30000; i++) {
		int pos = 0;
		LD d = dist(Point(x, y), p[0]);
		for (int j = 1; j < n; j++) {
			LD cur = dist(Point(x, y), p[j]);
			if (uax(d, cur))
				pos = j;
		}
		x += (p[pos].x - x) * shift;
		y += (p[pos].y - y) * shift;
		shift *= 0.999;
	}

	LD ans = 0;
	for (int i = 0; i < n; i++)
		uax(ans, dist(Point(x, y), p[i]));
	cout << ans;

#ifdef _DEBUG 
	cout << endl << "Time is " << (clock() - start) / 1000.0;
#endif
}

Measured memory_bytes: 256