#include <bits/stdc++.h>
using namespace std;
#define F first
#define S second
#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define trav(a, x) for(auto& a : x)
#define allin(a , x) for(auto a : x)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<ll> vl;
typedef vector<pii> vpi;
typedef pair<ll,ll> pll;
typedef vector<string> vs;
typedef vector<pll> vpl;
typedef vector<int> vi;
template<class T1, class T2>
istream &operator>>(istream &in, pair<T1, T2> &P){
    in >> P.first >> P.second;
    return in;
}
template<class T1, class T2>
ostream &operator<<(ostream &out, const pair<T1, T2> &P){
    out << "(" << P.first << ", " << P.second << ")";
    return out;
}
template<class T>
istream &operator>>(istream &in, vector<T> &arr){
    for(auto &x: arr) in >> x;
    return in;
}
template<class T>
ostream &operator<<(ostream &out, const vector<T> &arr){
    for(auto &x: arr) out << x << ' '; cout << "\n";
    return out;
}
template<class T>
istream &operator>>(istream &in, deque<T> &arr){
    for(auto &x: arr) in >> x;
    return in;
}
template<class T>
ostream &operator<<(ostream &out, const deque<T> &arr){
    for(auto &x: arr) out << x << ' '; cout << "\n";
    return out;
}
// begin of mclosing

template <class T> int sgn(T x) { return (x > 0) - (x < 0); }
template<class T>
struct Point {
	typedef Point P;
	T x, y;
	explicit Point(T x=0, T y=0) : x(x), y(y) {}
	bool operator<(P p) const { return tie(x,y) < tie(p.x,p.y); }
	bool operator==(P p) const { return tie(x,y)==tie(p.x,p.y); }
	P operator+(P p) const { return P(x+p.x, y+p.y); }
	P operator-(P p) const { return P(x-p.x, y-p.y); }
	P operator*(T d) const { return P(x*d, y*d); }
	P operator/(T d) const { return P(x/d, y/d); }
	T dot(P p) const { return x*p.x + y*p.y; }
	T cross(P p) const { return x*p.y - y*p.x; }
	T cross(P a, P b) const { return (a-*this).cross(b-*this); }
	T dist2() const { return x*x + y*y; }
	double dist() const { return sqrt((double)dist2()); }
	// angle to x-axis in interval [-pi, pi]
	double angle() const { return atan2(y, x); }
	P unit() const { return *this/dist(); } // makes dist()=1
	P perp() const { return P(-y, x); } // rotates +90 degrees
	P normal() const { return perp().unit(); }
	// returns point rotated 'a' radians ccw around the origin
	P rotate(double a) const {
		return P(x*cos(a)-y*sin(a),x*sin(a)+y*cos(a)); }
	friend ostream& operator<<(ostream& os, P p) {
		return os << "(" << p.x << "," << p.y << ")"; }
};

typedef Point<double> P;
double ccRadius(const P& A, const P& B, const P& C) {
	return (B-A).dist()*(C-B).dist()*(A-C).dist()/
			abs((B-A).cross(C-A))/2;
}
P ccCenter(const P& A, const P& B, const P& C) {
	P b = C-A, c = B-A;
	return A + (b*c.dist2()-c*b.dist2()).perp()/b.cross(c)/2;
}

pair<P, double> mec(vector<P> ps) {
	shuffle(all(ps), mt19937(time(0)));
	P o = ps[0];
	double r = 0, EPS = 1 + 1e-8;
	rep(i,0,sz(ps)) if ((o - ps[i]).dist() > r * EPS) {
		o = ps[i], r = 0;
		rep(j,0,i) if ((o - ps[j]).dist() > r * EPS) {
			o = (ps[i] + ps[j]) / 2;
			r = (o - ps[i]).dist();
			rep(k,0,j) if ((o - ps[k]).dist() > r * EPS) {
				o = ccCenter(ps[i], ps[j], ps[k]);
				r = (o - ps[i]).dist();
			}
		}
	}
	return {o, r};
}
// end

int32_t main(){
	int n;
	cin>>n;
	vector<P> v(n);
	rep(i,0,n){
		double x,y;
		cin>>x>>y;
		v[i] = P(x,y);
	}	
	cout<<fixed<<setprecision(9);
	cout << mec(v).second << endl;
}

Measured memory_bytes: 256