#pragma GCC optimize ("O3")
#include "bits/stdc++.h"

using namespace std;
using ll = long long int;

#define debugos cout
#define debug(v) {printf("L%d %s > ",__LINE__,#v);debugos<<(v)<<endl;}
#define debugv(v) {printf("L%d %s > ",__LINE__,#v);for(auto e:(v)){debugos<<e<<" ";}debugos<<endl;}
#define debuga(m,w) {printf("L%d %s > ",__LINE__,#m);for(int x=0;x<(w);x++){debugos<<(m)[x]<<" ";}debugos<<endl;}
#define debugaa(m,h,w) {printf("L%d %s >\n",__LINE__,#m);for(int y=0;y<(h);y++){for(int x=0;x<(w);x++){debugos<<(m)[y][x]<<" ";}debugos<<endl;}}
#define all(v) (v).begin(),(v).end()
#define repeat(cnt,l) for(auto cnt=remove_reference<decltype(l)>::type();(cnt)<(l);++(cnt))
#define rrepeat(cnt,l) for(auto cnt=(l)-1;0<=(cnt);--(cnt))
#define iterate(cnt,b,e) for(auto cnt=(b);(cnt)!=(e);++(cnt))
#define diterate(cnt,b,e) for(auto cnt=(b);(cnt)!=(e);--(cnt))
const ll MD = 1000000007ll; const long double PI = 3.1415926535897932384626433832795L;
inline void assert_call(bool assertion, function<void()> f) { if (!assertion) { cerr << "assertion fault:" << endl; f(); abort(); } }
template<typename T1, typename T2> inline ostream& operator <<(ostream &o, const pair<T1, T2> p) { o << '(' << p.first << ':' << p.second << ')'; return o; }
template<typename Vec> inline ostream& _ostream_vecprint(ostream& os, const Vec& a) {
  os << '['; for (const auto& e : a) os << ' ' << e << ' '; os << ']'; return os; }
template<typename T> inline ostream& operator<<(ostream& o, const vector<T>& v) { return _ostream_vecprint(o, v); }
template<typename T, size_t S> inline ostream& operator<<(ostream& o, const array<T, S>& v) { return _ostream_vecprint(o, v); }
template<typename T> inline T& chmax(T& to, const T& val) { return to = max(to, val); }
template<typename T> inline T& chmin(T& to, const T& val) { return to = min(to, val); }
void bye(string s, int code = 0) { cout << s << endl; exit(code); }
mt19937_64 randdev(8901016);
template<typename T, typename Random = decltype(randdev), typename enable_if<is_integral<T>::value>::type* = nullptr>
inline T rand(T l, T h, Random& rand = randdev) { return uniform_int_distribution<T>(l, h)(rand); }
template<typename T, typename Random = decltype(randdev), typename enable_if<is_floating_point<T>::value>::type* = nullptr>
inline T rand(T l, T h, Random& rand = randdev) { return uniform_real_distribution<T>(l, h)(rand); }

#if defined(_WIN32) || defined(_WIN64)
#define getc_x _getc_nolock
#define putc_x _putc_nolock
#elif defined(__GNUC__)
#define getc_x getc_unlocked
#define putc_x putc_unlocked
#else
#define getc_x getc
#define putc_x putc
#endif
#define isvisiblechar(c) (0x21<=(c)&&(c)<=0x7E)
class MaiScanner {
  FILE* fp_;
public:
  inline MaiScanner(FILE* fp):fp_(fp){}
  template<typename T> void input_integer(T& var) noexcept {
    var = 0; T sign = 1;
    int cc = getc_x(fp_);
    for (; cc < '0' || '9' < cc; cc = getc_x(fp_))
      if (cc == '-') sign = -1;
    for (; '0' <= cc && cc <= '9'; cc = getc_x(fp_))
      var = (var << 3) + (var << 1) + cc - '0';
    var = var * sign;
  }
  inline int c() noexcept { return getc_x(fp_); }
  inline MaiScanner& operator>>(int& var) noexcept { input_integer<int>(var); return *this; }
  inline MaiScanner& operator>>(long long& var) noexcept { input_integer<long long>(var); return *this; }
  inline MaiScanner& operator>>(string& var) {
    int cc = getc_x(fp_);
    for (; !isvisiblechar(cc); cc = getc_x(fp_));
    for (; isvisiblechar(cc); cc = getc_x(fp_))
      var.push_back(cc);
    return *this;
  }
  template<typename IT> inline void in(IT begin, IT end) { for (auto it = begin; it != end; ++it) *this >> *it; }
};
class MaiPrinter {
  FILE* fp_;
public:
  inline MaiPrinter(FILE* fp):fp_(fp){}
  template<typename T>
  void output_integer(T var) noexcept {
    if (var == 0) { putc_x('0', fp_); return; }
    if (var < 0)
      putc_x('-', fp_),
      var = -var;
    char stack[32]; int stack_p = 0;
    while (var)
      stack[stack_p++] = '0' + (var % 10),
      var /= 10;
    while (stack_p)
      putc_x(stack[--stack_p], fp_);
  }
  inline MaiPrinter& operator<<(char c) noexcept { putc_x(c, fp_); return *this; }
  inline MaiPrinter& operator<<(int var) noexcept { output_integer<int>(var); return *this; }
  inline MaiPrinter& operator<<(long long var) noexcept { output_integer<long long>(var); return *this; }
  inline MaiPrinter& operator<<(char* str_p) noexcept { while (*str_p) putc_x(*(str_p++), fp_); return *this; }
  inline MaiPrinter& operator<<(const string& str) {
    const char* p = str.c_str();
    const char* l = p + str.size();
    while (p < l) putc_x(*p++, fp_);
    return *this;
  }
  template<typename IT> void join(IT begin, IT end, char sep = ' ') { for (bool b = 0; begin != end; ++begin, b = 1) b ? *this << sep << *begin : *this << *begin; }
};
MaiScanner scanner(stdin);
MaiPrinter printer(stdout);


struct P {
  using value_t = double;
  value_t x, y;
  P(value_t _x = 0, value_t _y = 0) : x(_x), y(_y) {}
  inline void normalize() {
    if (x != 0 || y != 0)
      x /= hypot(), y /= hypot();
  }
  inline value_t hypot() const { return std::hypot(x, y); }
  inline value_t hypot(P p) const { return std::hypot(x - p.x, y - p.y); }
  inline value_t dot(P p) const { return x * p.x + y * p.y; }
  inline value_t cross(P p) const { return x * p.y - y * p.x; }
  inline P normalized() const { return x != 0 || y != 0 ? P(x / hypot(), y / hypot()) : P(0, 0); }
  inline P operator+(P p) const { return P(x + p.x, y + p.y); }
  inline P operator-(P p) const { return P(x - p.x, y - p.y); }
  inline P& operator+=(P p) {
    x += p.x;
    y += p.y;
    return *this;
  }
  inline P& operator-=(P p) {
    x -= p.x;
    y -= p.y;
    return *this;
  }
};
P operator*(P::value_t a, P p) {
  return P(a * p.x, a * p.y);
}


//


int N;
P pp[55];

//

constexpr double inf = 1e99;
constexpr double eps = 1e-10;

bool validate_radius(P center, double r) {
  repeat(i, N) {
    if (center.hypot(pp[i])-r > eps) return false;
  }
  return true;
}

pair<P, bool> calc_center(P a, P b) {
  a += b;
  a.x /= 2;
  a.y /= 2;
  return {a, true};
}

pair<P, bool> calc_center(P a, P b, P c) {
  double p = a.x - b.x;
  double q = a.y - b.y;
  double r = b.x - c.x;
  double s = b.y - c.y;
  
  double d = 2*(p*s-q*r);
  if (abs(d) < eps) return {P{}, false};
  double e1 = pow(a.hypot(), 2) - pow(b.hypot(), 2);
  double e2 = pow(b.hypot(), 2) - pow(c.hypot(), 2);
  double x = (s*e1 -q*e2)/d;
  double y = (-r*e1+p*e2)/d;
  return {P{x, y}, true};
}

int main() {
  scanner >> N;
  repeat(i, N) {
    int x, y;
    scanner >> x >> y;
    pp[i] = {double(x), double(y)};
  }
  
  
  double best = inf;
  
  repeat(i, N-1) {
    iterate(j, i+1, N) {
      
      P c = calc_center(pp[i], pp[j]).first;
      double d = c.hypot(pp[i]);
      if (validate_radius(c, d))
        chmin(best, d);
        
    }
  }
  
  if (N >= 3) {
    repeat(i, N-2) {
      iterate(j, i+1, N-1) {
        iterate(k, i+2, N) {
          
          auto cf = calc_center(pp[i], pp[j], pp[k]);
          if (!cf.second) continue;
          auto c = cf.first;
          double d = c.hypot(pp[i]);
          if (validate_radius(c, d))
            chmin(best, d);
          
        }
      }
    }
  }
  
  printf("%.14f\n", best);
  
  return 0;
}


Measured memory_bytes: 256