#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;

#define REP(i,n) for(long long i = 0; i < (n); i++)
#define FOR(i, m, n) for(long long i = (m);i < (n); ++i)
#define ALL(obj) (obj).begin(),(obj).end()
#define SPEED cin.tie(0);ios::sync_with_stdio(false);

template<class T> using V = vector<T>;
// template<class T, class U> using P = pair<T, U>;
template<class T> using PQ = priority_queue<T>;
template<class T> using PQR = priority_queue<T,vector<T>,greater<T>>;

constexpr long long MOD = (long long)1e9 + 7;
constexpr long long MOD2 = 998244353;
constexpr long long HIGHINF = (long long)1e18;
constexpr long long LOWINF = (long long)1e15;
constexpr long double PI = 3.1415926535897932384626433;

template <class T> vector<T> multivector(size_t N,T init){return vector<T>(N,init);}
template <class... T> auto multivector(size_t N,T... t){return vector<decltype(multivector(t...))>(N,multivector(t...));}
template <class T> void corner(bool flg, T hoge) {if (flg) {cout << hoge << endl; exit(0);}}
template <class T, class U>ostream &operator<<(ostream &o, const map<T, U>&obj) {o << "{"; for (auto &x : obj) o << " {" << x.first << " : " << x.second << "}" << ","; o << " }"; return o;}
template <class T>ostream &operator<<(ostream &o, const set<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
template <class T>ostream &operator<<(ostream &o, const multiset<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
template <class T>ostream &operator<<(ostream &o, const vector<T>&obj) {o << "{"; for (int i = 0; i < (int)obj.size(); ++i)o << (i > 0 ? ", " : "") << obj[i]; o << "}"; return o;}
template <class T, class U>ostream &operator<<(ostream &o, const pair<T, U>&obj) {o << "{" << obj.first << ", " << obj.second << "}"; return o;}
template <template <class tmp>  class T, class U> ostream &operator<<(ostream &o, const T<U> &obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr)o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
void print(void) {cout << endl;}
template <class Head> void print(Head&& head) {cout << head;print();}
template <class Head, class... Tail> void print(Head&& head, Tail&&... tail) {cout << head << " ";print(forward<Tail>(tail)...);}
template <class T> void chmax(T& a, const T b){a=max(a,b);}
template <class T> void chmin(T& a, const T b){a=min(a,b);}
void YN(bool flg) {cout << (flg ? "YES" : "NO") << endl;}
void Yn(bool flg) {cout << (flg ? "Yes" : "No") << endl;}
void yn(bool flg) {cout << (flg ? "yes" : "no") << endl;}

template <class T> class smallestEnclosingDisc{
    inline T cross(const complex<T>& a, const complex<T>& b) {return a.real()*b.imag() - a.imag()*b.real(); }
    inline T dot(const complex<T>& a, const complex<T>& b) { return a.real()*b.real() + a.imag()*b.imag(); }
    inline void makeCenter(const complex<T>& a,const complex<T>& b) {
        center = (a+b)/2.;
        radius = abs(a-center);
    }
    inline void makeCenter(const complex<T>& a,const complex<T>& b,const complex<T>& c) {
        T s = norm(b-c),t = norm(c-a),u = norm(a-b),z = abs(cross(b-a,c-a));
        center = (s*(t+u-s)*a+t*(u+s-t)*b+u*(s+t-u)*c)/(4*z*z);
        radius = abs(a-center);
    }
    inline bool isInCircle(const complex<T>& point){
        return norm(point-center) <= radius*radius + eps;
    } 
    vector<complex<T>> points;
    T eps;
public:
    complex<T> center;
    T radius;

    smallestEnclosingDisc(T eps = 1e-9): eps(eps){
    }
    inline void addPoint(complex<T> point){
        points.push_back(point);
    }
    void solve(){
        int num = points.size();
        if(num == 1) {
            radius = 0;
            center = points.front();
            return;
        }
        random_device seed_gen;
        mt19937 engine(seed_gen());
        shuffle(points.begin(), points.end(), engine);
        makeCenter(points[0],points[1]);
        for(int i = 2; i < num; ++i){
            if(isInCircle(points[i])) continue;
            makeCenter(points[0],points[i]);
            for(int j = 1; j < i; ++j) {
                if(isInCircle(points[j])) continue;
                makeCenter(points[i],points[j]);
                for(int k = 0; k < j; ++k) {
                    if(isInCircle(points[k])) continue;
                    makeCenter(points[i],points[j],points[k]);
                }
            }
        }
    }
};

//verify https://atcoder.jp/contests/abc151/tasks/abc151_f

int main() {
    int N; cin >> N;
	double X,Y;
    smallestEnclosingDisc<double> sed;
	for(int i = 0; i < N; ++i) {
		cin >> X >> Y;
        sed.addPoint(complex<double>(X,Y));
    }
    sed.solve();
    printf("%.10f",sed.radius);
    return 0;
}

Measured memory_bytes: 256