/**
 * code generated by JHelper
 * More info: https://github.com/AlexeyDmitriev/JHelper
 * @author aajisaka
 */

#include<bits/stdc++.h>

using namespace std;

void debug_out() { cerr << endl; }
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}
#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif

#define SPEED ios_base::sync_with_stdio(false);cin.tie(nullptr)
#define rep(i,n) for(int i=0; i<(int)(n); i++)
#define all(v) v.begin(), v.end()
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }

using ll = long long;
using P = pair<ll, ll>;

constexpr long double PI = 3.14159265358979323846264338327950288L;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

typedef double Real;

Real EPS = 1e-8;

int sgn(Real a, Real b=0){return a<b-EPS?-1:a>b+EPS?1:0;}
Real sqr(Real a){return sqrt(max(a,(Real)0));}

struct Point{
    Real add(Real a, Real b){
      if(abs(a+b) < EPS*(abs(a)+abs(b)))return 0;
      return a+b;
    }

    Real x, y;
    Point(){}
    Point(Real x,Real y) : x(x) , y(y){}

    Point operator + (Point p){return Point(add(x,p.x), add(y,p.y));}
    Point operator - (Point p){return Point(add(x,-p.x), add(y,-p.y));}
    Point operator * (Real d){return Point(x*d,y*d);}
    Point operator / (Real d){return Point(x/d,y/d);}
    bool operator == (Point p){return !sgn(dist(p));}
    //昇順
    bool operator < (Point p)const{return (p.x!=x)?x<p.x:y<p.y;}
    Real norm(){return sqr(x*x+y*y);}
    Real dist(Point a){return (*this-a).norm();}
    Real dot(Point a){return x*a.x+y*a.y;}
    Real cross(Point a){return x*a.y-y*a.x;}
};

struct Circle{
    Point p;
    Real r;
    Circle(){}
    Circle(Point p, Real r) : p(p) , r(r){}

    bool contain(Point a){
      return sgn((a-p).norm(),r)<=0;
    }

    Circle circumCircle(Point a,Point b){
      Point q=(a+b)/2;
      return Circle(q,(a-q).norm());
    }

    Circle circumscribedCircle(Point p, Point q, Point r){
      Point a=(q-p)*2,b=(r-p)*2;
      Point c(p.dot(p)-q.dot(q),p.dot(p)-r.dot(r));
      Circle res;
      res.p.x=a.y*c.y-b.y*c.x;
      res.p.y=b.x*c.x-a.x*c.y;
      res.p=res.p/a.cross(b);
      return Circle(res.p, p.dist(res.p));
    }

    Circle minEnclosingCircle(vector<Point>ps){
      if(ps.size()==0)return Circle(Point(0,0),0);
      if(ps.size()==1)return Circle(ps[0],0);

      Circle circle=circumCircle(ps[0],ps[1]);
      for(int i=2;i<ps.size();i++){
        if(!circle.contain(ps[i])){
          circle=circumCircle(ps[0],ps[i]);
          for(int j=1;j<i;j++){
            if(!circle.contain(ps[j])){
              circle=circumCircle(ps[j],ps[i]);
              for(int k=0;k<j;k++){
                if(!circle.contain(ps[k])){
                  circle=circumscribedCircle(ps[i],ps[j],ps[k]);
                }
              }
            }
          }
        }
      }
      return circle;
    }
};

class FEncloseAll {
public:

    void solve(istream& cin, ostream& cout) {
      SPEED;
      int n; cin >> n;
      vector<Point> ps(n);
      rep(i, n) {
        cin >> ps[i].x >> ps[i].y;
      }
      Circle c;
      auto ans = c.minEnclosingCircle(ps).r;

      cout << setprecision(10) << fixed;
      cout << ans << endl;
    }
};

signed main() {
  FEncloseAll solver;
  std::istream& in(std::cin);
  std::ostream& out(std::cout);
  solver.solve(in, out);
  return 0;
}

Measured memory_bytes: 256