#include<iostream>
#include<fstream>
#include<sstream>
#include<algorithm>
#include<vector>
#include<queue>
#include<map>
#include<set>
#include<string>
#include<cmath>
#include<cstdio>
#include<cassert>
#include<iomanip>

using namespace std;

#define REP(i,m,n) for(int i=(m); i<(int)(n); i++)
#define RREP(i,m,n) for(int i=(int)(n-1); i>=m; i--)
#define rep(i,n) REP(i,0,n)
#define rrep(i,n) RREP(i,0,n)
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
#define aut(r,v) __typeof(v) r = (v)
#define each(it,o) for(aut(it,(o).begin()); it!=(o).end(); ++it)
#define reach(it,o) for(aut(it,(o).rbegin()); it!=(o).rend(); ++it)
#define fi first
#define se second
#define debug(...) {cerr<<"[L"<<__LINE__<<"] "; _debug(__VA_ARGS__);}

template<typename T1, typename T2> ostream& operator<<(ostream& o, const pair<T1, T2>& p)
{return o<<"("<<p.first<<", "<<p.second<<")";}
template<typename T>string join(const vector<T>&v, string del=", ")
{stringstream s;rep(i,v.size())s<<del<<v[i];return s.str().substr(del.size());}
template<typename T>ostream& operator<<(ostream& o, const vector<T>&v)
{if(v.size())o<<"["<<join(v)<<"]";return o;}
template<typename T>ostream& operator<<(ostream& o, const vector<vector<T> >&vv)
{int l=vv.size();if(l){o<<endl;rep(i,l){o<<(i==0?"[ ":",\n  ")<<vv[i]<<(i==l-1?" ]":"");}}return o;}
template<typename T>ostream& operator<<(ostream& o, const set<T>& st)
{vector<T> v(st.begin(),st.end());o<<"{ "<<join(v)<<" }";return o;}
template<typename T1, typename T2>ostream& operator<<(ostream& o, const map<T1, T2>& m)
{each(p,m){o<<(p==m.begin()?"{ ":",\n  ")<<*p<<(p==--m.end()?" }":"");}return o;}
inline void _debug(){cerr<<endl;}
template<class First, class... Rest>
void _debug(const First& first, const Rest&... rest){cerr<<first<<" ";_debug(rest...);}

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<vl> vvl;

const double PI = (1*acos(0.0));
const double INF = 0x3f3f3f3f;
const double INFL = 0x3f3f3f3f3f3f3f3fLL;
const double EPS = 1e-9;
const double mod = 1e9 + 7;

inline void finput(string filename) {
    freopen(filename.c_str(), "r", stdin);
}

int N;
struct Point { double x, y; };
vector<Point> P;

double dist(Point a, Point b){
    double dx = a.x - b.x;
    double dy = a.y - b.y;
    return sqrt(dx*dx + dy*dy);
}

int main(){
    ios_base::sync_with_stdio(0);
    // finput("./input");

    cin >> N;
    P = vector<Point>(N);
    rep(i,N) cin >> P[i].x >> P[i].y;

    auto func = [&](double x, double y){
        double res = 0;
        rep(i,N){
            res = max(res, dist(Point{x, y}, P[i]));
        }
        return res;
    };
    auto tsx = [&](double x){
        double l = 0, r = 1000;
        rep(i,100){
            double c1 = (l*2+r)/3;
            double c2 = (l+r*2)/3;
            if(func(x,c1) > func(x,c2)) l = c1;
            else r = c2;
        }
        return func(x,l);
    };
    auto ts = [&](){
        double l = 0, r = 1000;
        rep(i,100){
            double c1 = (l*2+r)/3;
            double c2 = (l+r*2)/3;
            if(tsx(c1) > tsx(c2)) l = c1;
            else r = c2;
            debug(l,r,tsx(l));
        }
        return tsx(l);
    };
    cout << fixed << setprecision(10) << ts() << endl;
    return 0;
}


Measured memory_bytes: 256