#include <bits/stdc++.h>
#include <sys/time.h>
using namespace std;

#define rep(i,n) for(long long i = 0; i < (long long)(n); i++)
#define repi(i,a,b) for(long long i = (long long)(a); i < (long long)(b); i++)
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define fi first
#define se second
#define mt make_tuple
#define mp make_pair
template<class T1, class T2> bool chmin(T1 &a, T2 b) { return b < a && (a = b, true); }
template<class T1, class T2> bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }

using ll = long long; using vll = vector<ll>; using vvll = vector<vll>; using P = pair<ll, ll>;
ll ugauss(ll a, ll b) { if (!a) return 0; if (a>0^b>0) return a/b; else return (a+(a>0?-1:1))/b+1; }
ll lgauss(ll a, ll b) { if (!a) return 0; if (a>0^b>0) return (a+(a>0?-1:1))/b-1; else return a/b; }
template <typename T, typename U> ostream &operator<<(ostream &o, const pair<T, U> &v) {  o << "(" << v.first << ", " << v.second << ")"; return o; }
template<size_t...> struct seq{}; template<size_t N, size_t... Is> struct gen_seq : gen_seq<N-1, N-1, Is...>{}; template<size_t... Is> struct gen_seq<0, Is...> : seq<Is...>{};
template<class Ch, class Tr, class Tuple, size_t... Is>
void print_tuple(basic_ostream<Ch,Tr>& os, Tuple const& t, seq<Is...>){ using s = int[]; (void)s{0, (void(os << (Is == 0? "" : ", ") << get<Is>(t)), 0)...}; }
template<class Ch, class Tr, class... Args> 
auto operator<<(basic_ostream<Ch, Tr>& os, tuple<Args...> const& t) -> basic_ostream<Ch, Tr>& { os << "("; print_tuple(os, t, gen_seq<sizeof...(Args)>()); return os << ")"; }
ostream &operator<<(ostream &o, const vvll &v) { rep(i, v.size()) { rep(j, v[i].size()) o << v[i][j] << " "; o << endl; } return o; }
template <typename T> ostream &operator<<(ostream &o, const vector<T> &v) { o << '['; rep(i, v.size()) o << v[i] << (i != v.size()-1 ? ", " : ""); o << "]";  return o; }
template <typename T> ostream &operator<<(ostream &o, const deque<T> &v) { o << '['; rep(i, v.size()) o << v[i] << (i != v.size()-1 ? ", " : ""); o << "]";  return o; }
template <typename T>  ostream &operator<<(ostream &o, const set<T> &m) { o << '['; for (auto it = m.begin(); it != m.end(); it++) o << *it << (next(it) != m.end() ? ", " : ""); o << "]";  return o; }
template <typename T>  ostream &operator<<(ostream &o, const unordered_set<T> &m) { o << '['; for (auto it = m.begin(); it != m.end(); it++) o << *it << (next(it) != m.end() ? ", " : ""); o << "]";  return o; }
template <typename T, typename U>  ostream &operator<<(ostream &o, const map<T, U> &m) { o << '['; for (auto it = m.begin(); it != m.end(); it++) o << *it << (next(it) != m.end() ? ", " : ""); o << "]";  return o; }
template <typename T, typename U, typename V>  ostream &operator<<(ostream &o, const unordered_map<T, U, V> &m) { o << '['; for (auto it = m.begin(); it != m.end(); it++) o << *it; o << "]";  return o; }
vector<int> range(const int x, const int y) { vector<int> v(y - x + 1); iota(v.begin(), v.end(), x); return v; }
template <typename T> istream& operator>>(istream& i, vector<T>& o) { rep(j, o.size()) i >> o[j]; return i;}
template <typename T, typename S, typename U> ostream &operator<<(ostream &o, const priority_queue<T, S, U> &v) { auto tmp = v; while (tmp.size()) { auto x = tmp.top(); tmp.pop(); o << x << " ";} return o; }
template <typename T> ostream &operator<<(ostream &o, const queue<T> &v) { auto tmp = v; while (tmp.size()) { auto x = tmp.front(); tmp.pop(); o << x << " ";} return o; }
template <typename T> ostream &operator<<(ostream &o, const stack<T> &v) { auto tmp = v; while (tmp.size()) { auto x = tmp.top(); tmp.pop(); o << x << " ";} return o; }
template <typename T> unordered_map<T, ll> counter(vector<T> vec){unordered_map<T, ll> ret; for (auto&& x : vec) ret[x]++; return ret;};
void vizGraph(vvll& g, int mode = 0, string filename = "out.png") { ofstream ofs("./out.dot"); ofs << "digraph graph_name {" << endl; set<P> memo; rep(i, g.size())  rep(j, g[i].size()) { if (mode && (memo.count(P(i, g[i][j])) || memo.count(P(g[i][j], i)))) continue; memo.insert(P(i, g[i][j])); ofs << "    " << i << " -> " << g[i][j] << (mode ? " [arrowhead = none]" : "")<< endl;  } ofs << "}" << endl; ofs.close(); system(((string)"dot -T png out.dot >" + filename).c_str()); }
struct timeval start; double sec() { struct timeval tv; gettimeofday(&tv, NULL); return (tv.tv_sec - start.tv_sec) + (tv.tv_usec - start.tv_usec) * 1e-6; }
size_t random_seed; struct init_{init_(){ ios::sync_with_stdio(false); cin.tie(0); gettimeofday(&start, NULL); struct timeval myTime; struct tm *time_st; gettimeofday(&myTime, NULL); time_st = localtime(&myTime.tv_sec); srand(myTime.tv_usec); random_seed = RAND_MAX / 2 + rand() / 2; }} init__;
#define ldout fixed << setprecision(40) 

#define EPS (double)1e-10
#define INF (ll)1e18
#define mo  (ll)(1e9+7)

// (x-cx)^2+(y-cy)^2<=r
bool is_in(long double cx, long double cy, long double r, long double x, long double y) {
    return (x-cx)*(x-cx)+(y-cy)*(y-cy)<=r*r+EPS;

}

ll calc(long double x1, long double y1, long double x2, long double y2, long double x3, long double y3, long double *cx, long double *cy, long double *r)
{
	long double 	ox, oy, a, b, c, d ;
	long double 	r1, r2, r3 ;
	long double		stat ;

	a = x2 - x1 ;
	b = y2 - y1 ;
	c = x3 - x1 ;
	d = y3 - y1 ;

	stat = -1 ;

	if  ((a && d) || (b && c)) {
        if (a * d - b * c == 0) return -1;
		ox = x1 + (d * (a * a + b * b) - b * (c * c + d * d)) / (a * d - b * c) / 2. ;
		if  (b) {
            if (b == 0) return -1;
			oy = (a * (x1 + x2 - ox - ox) + b * (y1 + y2)) / b / 2. ;
		} else {
            if (d == 0) return -1;
			oy = (c * (x1 + x3 - ox - ox) + d * (y1 + y3)) / d / 2. ;
		}
		r1   = sqrt((ox - x1) * (ox - x1) + (oy - y1) * (oy - y1)) ;
		r2   = sqrt((ox - x2) * (ox - x2) + (oy - y2) * (oy - y2)) ;
		r3   = sqrt((ox - x3) * (ox - x3) + (oy - y3) * (oy - y3)) ;
		*cx = ox ;
		*cy = oy ;
		*r  = (r1 + r2 + r3) / 3. ;
		stat = 0 ;
	}

	return stat ;
}

int main(void) {
    ll n; cin >> n;
    vector<long double> x(n), y(n);
    rep(i, n) cin >> x[i] >> y[i];
    long double ret = 10000;
    rep(i, n) rep(j, n) if (i != j) {
        long double r = sqrt(pow(x[i]-x[j],2)+pow(y[i]-y[j],2))/2.;
        long double cx = (x[i]+x[j])/2.;
        long double cy = (y[i]+y[j])/2.;
        ll faf = 1; rep(h, n) faf &= is_in(cx,cy,r,x[h],y[h]); if (faf) chmin(ret, r);
    }
    rep(i, n) repi(j, i + 1, n) repi(l, j + 1, n) {
        long double r, cx, cy;
        ll s = calc(x[i], y[i], x[j], y[j], x[l], y[l], &cx, &cy, &r);
        if (s == 0) {
            ll faf = 1; rep(h, n) faf &= is_in(cx,cy,r,x[h],y[h]); if (faf) chmin(ret, r);
        }
    }
    cout << ldout << ret << endl;


    return 0;
}


Measured memory_bytes: 384