#include <bits/stdc++.h>
using namespace std;
#define REP(i,b,e) for(int i=(b);i<(e);++i)
#define RREP(i,b,e) for(int i=(b)-1;i>=e;--i)
#define rep(i,e) for(int i=0;i<(e);++i)

constexpr int MOD = 1000000007;
constexpr int INF = 1LL << 30;
constexpr long long LLINF = 1LL << 62;
constexpr double EPS = 1e-9;

struct Initializer {
  Initializer() {
    cin.tie(0);
    ios::sync_with_stdio(0);
    cout << fixed << setprecision(15) << boolalpha;
  }
} initializer;

template<typename T>
istream &operator>>(istream &is, vector<T> &vec) {
  for (T &x : vec) is >> x;
  return is;
}

template<typename T>
ostream &operator<<(ostream &os, const vector<T> &vec) {
  os << "[";
  for (auto it = vec.begin(); it != vec.end(); ++it) {
    if (it != vec.begin()) os << ", ";
    os << *it;
  }
  return os << "]";
}

template<typename T, typename U>
ostream &operator<<(ostream &os, const pair<T, U> &pa) {
  return os << "(" << pa.first << ", " << pa.second << ")";
}

template<typename Tuple, size_t N>
struct TuplePrinter {
  static void print(const Tuple &t) {
    TuplePrinter<Tuple, N-1>::print(t);
    cout << ", " << get<N-1>(t);
  }
};

template<typename Tuple>
struct TuplePrinter<Tuple, 1> {
  static void print(const Tuple &t) {
    cout << get<0>(t);
  }
};

template<typename... T>
ostream &operator<<(ostream &os, const tuple<T...> &tup) {
  os << "(";
  TuplePrinter<decltype(tup), sizeof...(T)>::print(tup);
  return os << ")";
}

template<typename T>
ostream &operator<<(ostream &os, const set<T> &se) {
  os << "{";
  for (auto it = se.begin(); it != se.end(); ++it) {
    if (it != se.begin()) os << ", ";
    os << *it;
  }
  return os << "}";
}

template<typename T, typename U>
ostream &operator<<(ostream &os, const map<T, U> &ma) {
  os << "{";
  for (auto it = ma.begin(); it != ma.end(); ++it) {
    if (it != ma.begin()) os << ", ";
    os << it->first << ": " << it->second;
  }
  return os << "}";
}

inline void print(void) { cout<<'\n'; }
template<class T> inline void print(const T &x) { cout<<x<<'\n'; }
template<class T, class... U> inline void print(const T &x, const U&... y) { cout<<x<<" "; print(y...); }
#define dump(...) cout<<#__VA_ARGS__<<": [L_"<<__LINE__<<"]"<<'\n'; print(__VA_ARGS__);cout<<'\n';

template<class T, class U>inline bool chmax(T &a, const U &b) { if(a<b){ a=b; return 1; } return 0; }
template<class T, class U>inline bool chmin(T &a, const U &b) { if(b<a){ a=b; return 1; } return 0; }


int main() {
  int n; cin>>n;
  vector<double> x(n), y(n);
  rep(i, n) cin>>x[i]>>y[i];
  double ans = 1e9;

  rep(i, n) REP(j, i+1, n) REP(k, j+1, n) {
    double xt, yt;
    double a = x[i], b = y[i], c = x[j], d = y[j], e = x[k], f = y[k];
    yt = ((e-a)*(a*a+b*b-c*c-d*d)-(c-a)*(a*a+b*b-e*e-f*f))/(2*(e-a)*(b-d)-2*(c-a)*(b-f));
    if (c == a) {
      xt = ((double)2*(b-f)*yt-a*a-b*b+e*e+f*f)/((double)2*(e-a));
    } else {
      xt = ((double)2*(b-d)*yt-a*a-b*b+c*c+d*d)/((double)2*(c-a));
    }
    double diff = sqrt((x[i]-xt)*(x[i]-xt)+(y[i]-yt)*(y[i]-yt));
    
    bool flag = true;
    rep(l, n) {
      if (l == i or l == j or l == k) continue;
        double dt = sqrt((x[l]-xt)*(x[l]-xt)+(y[l]-yt)*(y[l]-yt));
        if (dt > diff) flag = false;
    }
    if (flag) ans = min(ans, diff);
  }

  rep(i, n) REP(j, i+1, n) {
    double xt, yt;
    xt = (x[i]+x[j]) / 2;
    yt = (y[i]+y[j]) / 2;
    double diff = sqrt((x[i]-xt)*(x[i]-xt)+(y[i]-yt)*(y[i]-yt));
  
    bool flag = true;
    rep(l, n) {
      if (l == i or l == j) continue;
        double dt = sqrt((x[l]-xt)*(x[l]-xt)+(y[l]-yt)*(y[l]-yt));
        if (dt > diff) flag = false;
    }
    if (flag) ans = min(ans, diff);
  }
  print(ans);

  return 0;
}

Measured memory_bytes: 256