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

// region template
#define rep(i, a, b) for (int i = (a); i < (b); ++i)
#define trav(a, x) for (auto &a : x)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef vector<int> vi;

ll gcd(ll a, ll b) { return __gcd(a, b); }

ll euclid(ll a, ll b, ll &x, ll &y) {
    if (b) { ll d = euclid(b, a % b, y, x);
        return y -= a/b * x, d; }
    return x = 1, y = 0, a;
}

typedef unsigned long long ull;
typedef long double ld;
ull mod_mul(ull a, ull b, ull M) {
    ll ret = a * b - M * ull(ld(a) * ld(b) / ld(M));
    return ret + M * (ret < 0) - M * (ret >= (ll)M);
}
ull mod_pow(ull b, ull e, ull mod) {
    ull ans = 1;
    for (; e; b = mod_mul(b, b, mod), e /= 2)
        if (e & 1) ans = mod_mul(ans, b, mod);
    return ans;
}

const ll mod = 1000000007;
struct Mod {
    ll x;
    Mod(ll xx) : x(xx) {}
    Mod operator+(Mod b) { return Mod((x + b.x) % mod); }
    Mod operator-(Mod b) { return Mod((x - b.x) % mod); }
    Mod operator*(Mod b) { return Mod((x * b.x) % mod); }
    Mod operator/(Mod b) { return *this * invert(b); }
    Mod invert(Mod a) {
        ll x, y, g = euclid(a.x, mod, x, y);
        assert(g == 1); return Mod((x + mod) % mod);
    }
    Mod operator^(ll e) {
        if (!e) return Mod(1);
        Mod r = *this ^ (e / 2); r = r * r;
        return e & 1 ? *this * r : r;
    }
};
// endregion

// Point.h, circumcircle.h, MinimumEnclosingCircle.h
template<class T> int sgn(T x) { return (x > 0) - (x < 0); }
template<class T> struct Point {
    typedef Point P;
    T x, y;
    explicit Point(T x=0, T y=0) : x(x), y(y) {}
    bool operator<(P p) const { return tie(x, y) < tie(p.x, p.y); }
    bool operator==(P p) const { return tie(x, y) == tie(p.x, p.y); }
    P operator+(P p) const { return P(x+p.x, y+p.y); }
    P operator-(P p) const { return P(x-p.x, y-p.y); }
    P operator*(T d) const {return P(x*d, y*d);}
    P operator/(T d) const { return P(x/d, y/d); }
    T dot(P p) const { return x*p.x+y*p.y; }
    T cross(P p) const { return x*p.y-y*p.x; }
    T cross(P a,P b)const { return (a-*this).cross(b-*this); }
    T dist2() const { return x*x+y*y; }
    double dist()const { return sqrt((double)dist2()); }
    double angle() const { return atan2(y/x); }
    P unit() const { return *this/dist(); }
    P perp() const { return P(-y,x); }
    P normal() const { return perp().unit(); }
    P rotate(double a) const {
        return P(x*cos(a)-y*sin(a),x*sin(a)+y*cos(a));
    }
    friend ostream& operator<<(ostream& os,P p) {
        return os<<"("<<p.x<<","<<p.y<<")";
    }
};

typedef Point<double> P;
double ccRadius(const P& A, const P& B, const P& C) {
    return (B-A).dist()*(C-B).dist()*(A-C).dist()/abs((B-A).cross(C-A))/2;
}
P ccCenter(const P& A, const P& B, const P& C) {
    P b=C-A, c=B-A;
    return A+(b*c.dist2()-c*b.dist2()).perp()/b.cross(c)/2;
}

pair<P,double> mec(vector<P> ps) {
    shuffle(all(ps),mt19937(time(0)));
    P o=ps[0];
    double r=0,EPS=1+1e-8;
    rep(i,0,sz(ps)) if ((o-ps[i]).dist()>r*EPS){
        o=ps[i],r=0;
        rep(j,0,i) if((o-ps[j]).dist()>r*EPS){
            o=(ps[i]+ps[j])/2;
            r=(o-ps[i]).dist();
            rep(k,0,j) if((o-ps[k]).dist()>r*EPS){
                o=ccCenter(ps[i],ps[j],ps[k]);
                r=(o-ps[i]).dist();
            }
        }
    }
    return {o,r};
}

int main() {
    cin.sync_with_stdio(0); cin.tie(0); cin.exceptions(cin.failbit);

    vector<P> ps;
    int n;cin>>n;
    for(int i=0;i<n;i++){
        P p;
        cin>>p.x>>p.y;
        ps.push_back(p);
    }
    pair<P,double> m=mec(ps);
    cout<<fixed<<setprecision(15)<<m.second<<endl;
}

Measured memory_bytes: 256