// Slower C++ solution:
#include <bits/stdc++.h>



#define rep(i,n) for(int i=0;i<(int)(n);i++)

#define FOR(i,n,m) for(int i=(int)(n); i<=(int)(m); i++)

#define RFOR(i,n,m) for(int i=(int)(n); i>=(int)(m); i--)

#define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++)

#define RITR(x,c) for(__typeof(c.rbegin()) x=c.rbegin();x!=c.rend();x++)

#define setp(n) fixed << setprecision(n)



#define ld long double

#define ll long long

#define vll vector<ll>

#define vi vector<int>

#define pll pair<ll,ll>

#define pi pair<int,int>



#define all(a) (a.begin()),(a.end())

#define rall(a) (a.rbegin()),(a.rend())

#define fi first

#define se second

#define pb push_back

#define mp make_pair

#define ins insert



using namespace std;



/* Some Libraries */



//-------------------------------------------------



int main(void)

{

    cin.tie(0);

    ios::sync_with_stdio(false);

    using P = pair<double,double>;

    auto dist = [](P p1,P p2){

        double dx = (p1.fi-p2.fi);

        double dy = (p1.se-p2.se);

        return sqrt(dx*dx+dy*dy);

    };

    int n; cin>>n;

    vector<P> ps(n);

    rep(i,n){

        cin>>ps[i].fi>>ps[i].se;

    }

    auto f = [&](double x){

        double l=-1001, r=1001;

        rep(i,100){

            double c1=(l*2+r)/3;

            double c2=(l+r*2)/3;

            P p1(x,c1), p2(x,c2);

            double m1=0,m2=0;

            rep(i,n){

                m1=max(m1,dist(p1,ps[i]));

                m2=max(m2,dist(p2,ps[i]));

            }

            if (m1>m2) l=c1;

            else r=c2;

        }

        double ret=0;

        P cp(x,(l+r)/2);

        rep(i,n){

            ret=max(ret,dist(cp,ps[i]));

        }

        return ret;

    };

    double l=-1001, r=1001;

    rep(i,100){

        double c1=(l*2+r)/3;

        double c2=(l+r*2)/3;

        if (f(c1)>f(c2)) l = c1;

        else r = c2;

    }

    double ans=f((l+r)/2);

    cout<<setp(15)<<ans<<endl;

    return 0;

}


// Faster C++ solution for the same problem (measured speedup: 1.572053690984355x):
#include <bits/stdc++.h>



#define rep(i,n) for(int i=0;i<(int)(n);i++)

#define FOR(i,n,m) for(int i=(int)(n); i<=(int)(m); i++)

#define RFOR(i,n,m) for(int i=(int)(n); i>=(int)(m); i--)

#define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++)

#define RITR(x,c) for(__typeof(c.rbegin()) x=c.rbegin();x!=c.rend();x++)

#define setp(n) fixed << setprecision(n)



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

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



#define ll long long

#define vll vector<ll>

#define vi vector<int>

#define pll pair<ll,ll>

#define pi pair<int,int>



#define all(a) (a.begin()),(a.end())

#define rall(a) (a.rbegin()),(a.rend())

#define fi first

#define se second

#define pb push_back

#define mp make_pair

#define ins insert



using namespace std;



//-------------------------------------------------

//--Geometry Template (Plane)

//-------------------------------------------------



using lf = double;

const lf EPS = 1e-9;

const lf PI = acos(-1);



#define sgn(x) (((x)<-EPS)?-1:((x)>EPS)?1:0)

#define EQ(x,y) (sgn((y)-(x))==0)



struct V {

    lf x,y;

    V(){}

    V(lf x, lf y):x(x),y(y){}

    V(const V &v):x(v.x),y(v.y){}

    V& operator+=(const V &v){x+=v.x; y+=v.y; return *this;}

    V& operator-=(const V &v){x-=v.x; y-=v.y; return *this;}

    V& operator*=(lf k){x*=k; y*=k; return *this;}

    V& operator/=(lf k){x/=k; y/=k; return *this;}

    V operator+(const V &v){return V(*this)+=v;}

    V operator-(const V &v){return V(*this)-=v;}

    V operator*(lf k){return V(*this)*=k;}

    V operator/(lf k){return V(*this)/=k;}

    V operator-(){return V(-x,-y);}

    lf sq(){return x*x+y*y;}

    lf norm(){return sqrt(sq());}

    V unit(){return V(*this)/=norm();}

    lf arg(){return atan2(y,x);}

    V rot(lf c, lf s){return V(x*c-y*s,x*s+y*c);}

    V rot(lf a){return rot(sin(a),cos(a));}

    V rot90(){return V(-y,x);}

    bool operator<(const V &v){

        if (sgn(x-v.x)) return sgn(x-v.x)<0;

        return sgn(y-v.y)<0;

    }

    friend ostream& operator<<(ostream &os, const V &v){return os<<'('<<v.x<<", "<<v.y<<')';}

};



lf dot(const V &a, const V &b){return a.x*b.x+a.y*b.y;}

lf det(const V &a, const V &b){return a.x*b.y-a.y*b.x;}



int ccw(V a, V b, V c){

    b-=a; c-=a;

    if (sgn(det(b,c))>0) return 1;

    else if(sgn(det(b,c))<0) return -1;

    else if(sgn(dot(b,c))<0) return 2;

    else if(sgn(b.norm()-c.norm())<0) return -2;

    return 0;

}



struct Line {

    V p,q;

    Line(){}

    Line(const V &p, const V &q):p(p),q(q){}

    Line(const Line &l):Line(l.p,l.q){}

    V unit(){return (q-p).unit();}

    lf arg(){return (q-p).arg();}

    Line rot(lf c, lf s){return Line(p.rot(c,s),q.rot(c,s));}

    Line rot(lf a){return Line(p.rot(a),q.rot(a));}

    Line rot90(){return Line(p.rot90(),q.rot90());}

};



struct Segment : Line {

    Segment(){}

    Segment(const V &p, const V &q):Line(p,q){}

    Segment(const Segment &s):Line(s){}

    lf sq(){return (Line::q-Line::p).sq();}

    lf norm(){return (Line::q-Line::p).norm();}

};



// functions about lines

bool parallel(const V &a, const V &b){return EQ(det(a,b),0.0);}

bool parallel(Line &a, Line &b){return EQ(det(a.q-a.p,b.q-b.p),0.0);}

bool orthogonal(const V &a, const V &b){return EQ(dot(a,b),0.0);}

bool orthogonal(Line &a, Line &b){return EQ(dot(a.q-a.p,b.q-b.p),0.0);}



bool samel(Line &a, Line &b){return parallel(a,b)&&EQ(det(a.q-a.p,b.p-a.p),0.0);}

bool insec(Line &a, Line &b){return !parallel(a,b);}

bool insec(Segment &a, Segment &b){

    int c1 = ccw(a.p,a.q,b.p)*ccw(a.p,a.q,b.q);

    int c2 = ccw(b.p,b.q,a.p)*ccw(b.p,b.q,a.q);

    return (c1<=0 && c2<=0);

}

bool insec(Line &a, Segment &b){return ccw(a.p,a.q,b.p)*ccw(a.p,a.q,b.q)<=0;}



// use only if lines have intersection

V cpoint(Line &a, Line &b){

    V r(a.q-a.p);

    r *= det(b.p-a.p,b.q-b.p)/det(a.q-a.p,b.q-b.p);

    return a.p+r;

}



lf distance(V &a, V &b){return (b-a).norm();}

lf distance(Line &l, V &v){return abs(det((l.q-l.p).unit(),v-l.p));}

lf distance(Line &a, Line &b){return (parallel(a,b))?distance(a,b.p):0.0;}

lf distance(Segment &s, V &v){

    if (sgn(dot(s.q-s.p,v-s.p))<0) return distance(s.p,v);

    else if(sgn(dot(s.p-s.q,v-s.q))<0) return distance(s.q,v);

    return distance((Line&)s,v);

}

lf distance(Segment &a, Segment &b){

    if (insec(a,b)) return 0.0;

    lf A=min(distance(a,b.p),distance(a,b.q));

    lf B=min(distance(b,a.p),distance(b,a.q));

    return min(A,B);

}

lf distance(Line &a, Segment &b){

    if (insec(a,b)) return 0.0;

    return min(distance(a,b.p),distance(a,b.q));

}



V subdiv(V &a, V &b, lf m, lf n){return (a*n+b*m)/(m+n);}

V outside(V &a, V &b, lf m, lf n){return (-a*n+b*m)/(m-n);}

V ppfoot(Line &l, V &v){

    V u = (l.q-l.p).unit();

    return l.p+u*dot(u,v-l.p);

}

V reflect(Line &l, V &v){

    V f = ppfoot(l,v);

    return f+(f-v);

}



Line vbsector(V &a, V &b){

    V m = (a+b)/2;

    return Line(m, m+(b-a).rot90());

}

Line absector(V &c, V &a, V &b){

    lf m=(a-c).norm(), n=(b-c).norm();

    return Line(c,subdiv(a,b,m,n));

}

Line perpend(V &c, V &a, V &b){return Line(c,c+(b-a).rot90());}



//-------------------------------------------------

//--Polygon (depends on Geometry Template)

//-------------------------------------------------



//anti-clockwise

struct Polygon {

    vector<V> ps; int n;

    Polygon():n(0){}

    Polygon(int n):n(n),ps(n){}

    void push(const V &v){ps.push_back(v), n++;}

    void pop(){ps.pop_back(), n--;}

    V& operator[](int k){return ps[k%n];}

};



lf area(Polygon &p){

    lf ret=0.0;

    for(int i=0; i<p.n; i++)

        ret+=det(p[i],p[i+1])/2;

    return ret;

}



V gravity(Polygon &p){

    V ret(0,0); lf wsum=0.0;

    for(int i=0; i<p.n; i++){

        lf w = det(p[i],p[i+1]);

        ret+=(p[i]+p[i+1])*w;

        wsum+=w;

    }

    return ret/wsum/3;

}



bool convex(Polygon &p){

    for(int i=0; i<p.n; i++)

        if (sgn(det(p[i]-p[i+1],p[i+1]-p[i+2]))<0) return false;

    return true;

}



Polygon convex_full(vector<V> &ps){

    Polygon ret;

    sort(ps.begin(), ps.end());

    for(int i=0; i<ps.size(); i++){

        while(ret.n>1 && sgn(det(ret[ret.n-1]-ret[ret.n-2],ps[i]-ret[ret.n-1]))<=0) ret.pop();

        ret.push(ps[i]);

    }

    for(int i=ps.size()-2, t=ret.n; i>=0; i--){

        while(ret.n>t && sgn(det(ret[ret.n-1]-ret[ret.n-2],ps[i]-ret[ret.n-1]))<=0) ret.pop();

        ret.push(ps[i]);

    }

    ret.pop();

    return ret;

}



lf diameter(Polygon &p){

    if (p.n==2) return distance(p[0],p[1]);

    lf ret=0;

    int s=0,t=0;

    for(int i=0; i<p.n; i++)

        if (p[t]<p[i]) t = i;

    int ed=t;

    while(s!=ed || t!=p.n){

        chmax(ret, distance(p[s],p[t]));

        (sgn(det(p[s+1]-p[s], p[t]-p[t+1]))>0)? s++ : t++;

    }

    return ret;

}



Polygon convex_cut(Polygon &p, Line &l){

    Polygon ret;

    for(int i=0; i<p.n; i++){

        if (ccw(l.p,l.q,p[i])!=-1) ret.push(p[i]);

        if (ccw(l.p,l.q,p[i])*ccw(l.p,l.q,p[i+1])==-1){

            Segment s(p[i+1],p[i]);

            ret.push(cpoint(l,s));

        }

    }

    return ret;

}



// OUT=0, ON=1, IN=2

int contain(Polygon &p, const V &v){

    int ret=0;

    for(int i=0; i<p.n; i++){

        V a=p[i]-v, b=p[i+1]-v;

        if (a.y>b.y) swap(a,b);

        if (sgn(a.y)<0 && sgn(b.y)>=0 && sgn(det(a,b))<0) ret=2-ret;

        if (EQ(det(a,b),0.0) && sgn(dot(a,b))<=0) return 1;

    }

    return ret;

}



// OUT=0, ON=1, IN=2

int convex_contain(Polygon &p, V &v){

    V g = (p[0]+p[p.n/3]+p[p.n*2/3])/3;

    int lo=0, hi=p.n;

    while(hi-lo>1){

        int c=(lo+hi)/2;

        if (sgn(det(p[lo]-g,p[c]-g))>0){

            (sgn(det(p[lo]-g,v-g))>0 && sgn(det(p[c]-g,v-g))<0)? hi=c: lo=c;

        }else{

            (sgn(det(p[lo]-g,v-g))<0 && sgn(det(p[c]-g,v-g))>0)? lo=c: hi=c;

        }

    }

    return sgn(det(p[lo]-v,p[hi]-v))+1;

}



//-------------------------------------------------

//--Circle (depends on Geometry Template)

//-------------------------------------------------



struct Circle {

    V p; lf r;

    Circle(){}

    Circle(const V &v, lf r):p(v),r(r){}

    Circle(const Circle &c):p(c.p),r(c.r){}

    lf area(){return r*r*PI;}

    lf area(lf t){return r*r*t/2;}

};



// functons about circles

bool contain(Circle &c, V &v){return sgn(distance(v,c.p)-c.r)<=0;}

bool contain(Circle &c, Segment &s){

    return sgn(max(distance(s.p,c.p),distance(s.q,c.p))-c.r)<=0;

}

bool insec(Circle &c, Line &l){return sgn(distance(l,c.p)-c.r)<=0;}

bool insec(Circle &c, Segment &s){

    return sgn(distance(s,c.p)-c.r)<=0 && sgn(max(distance(s.p,c.p),distance(s.q,c.p))-c.r)>=0;

}



vector<V> cpoint(Circle &a, Circle &b){

    vector<V> ret;

    V ab(b.p-a.p);

    lf d = ab.norm(), dd = ab.sq();

    lf c = (a.r*a.r+dd-b.r*b.r)/(2.0*a.r*d);

    if (sgn(abs(c)-1.0)>0) return ret;

    if (EQ(abs(c),1.0)){

        c = (c>0)?1:-1;

        ret.push_back(a.p+ab.unit().rot(c,0)*a.r);

    }else{

        lf s = sqrt(1.0-c*c);

        ret.push_back(a.p+ab.unit().rot(c,s)*a.r);

        ret.push_back(a.p+ab.unit().rot(c,-s)*a.r);

    }

    return ret;

}



vector<V> cpoint(Circle &c, Line &l){

    vector<V> ret;

    lf d = distance(l,c.p);

    if (sgn(d-c.r)>0) return ret;

    V h = ppfoot(l,c.p);

    if (EQ(d,c.r)){

        ret.push_back(h);

    }else{

        V r = (l.q-l.p).unit()*sqrt(c.r*c.r-d*d);

        ret.push_back(h+r);

        ret.push_back(h-r);

    }

    return ret;

}



vector<V> cpoint(Circle &c, Segment &s){

    vector<V> ret,cand;

    cand = cpoint(c,(Line&)s);

    for(auto p:cand)if(sgn(dot(s.p-p,s.q-p))<=0)

        ret.push_back(p);

    return ret;

}



vector<V> tangent(Circle &c, const V &v){

    lf rr=(c.p-v).sq()-c.r*c.r;

    if (sgn(rr)<0) return vector<V>();

    Circle c2(v,sqrt(rr));

    return cpoint(c,c2);

}



vector<V> tangent(Circle &a, Circle &b){

    vector<V> ret, t;

    ret = tangent(a, subdiv(a.p,b.p,a.r,b.r));

    if (!EQ(a.r,b.r)){

        t = tangent(a, outside(a.p,b.p,a.r,b.r));

    }else{

        V r = (b.p-a.p).unit().rot90()*a.r;

        t.push_back(a.p+r);

        t.push_back(a.p-r);

    }

    for(auto p:t) ret.push_back(p);

    return ret;

}



vector<Line> tangent_line(Circle &c, const V &v){

    vector<Line> ret;

    auto t = tangent(c,v);

    for(auto p:t) ret.push_back(Line(v,p));

    return ret;

}



vector<Line> tangent_line(Circle &a, Circle &b){

    vector<Line> ret,t;

    ret = tangent_line(a, subdiv(a.p,b.p,a.r,b.r));

    if (!EQ(a.r,b.r)){

        t = tangent_line(a, outside(a.p,b.p,a.r,b.r));

    }else{

        V r = (b.p-a.p).unit().rot90()*a.r;

        t.push_back(Line(a.p+r, b.p+r));

        t.push_back(Line(a.p-r, b.p-r));

    }

    for(auto l:t) ret.push_back(l);

    return ret;

}



lf carea(Circle &a, Circle &b){

    lf d = distance(a.p,b.p);

    if (sgn(d+a.r-b.r)<=0) return a.area();

    if (sgn(d+b.r-a.r)<=0) return b.area();

    auto cps = cpoint(a,b);

    if (cps.size()<2) return 0.0;

    lf t1 = acos(dot((cps[1]-a.p).unit(),(cps[0]-a.p).unit()));

    if (sgn(det(cps[1]-a.p,cps[0]-a.p))<0) t1=2*PI-t1;

    lf t2 = acos(dot((cps[0]-b.p).unit(),(cps[1]-b.p).unit()));

    if (sgn(det(cps[0]-b.p,cps[1]-b.p))<0) t2=2*PI-t2;

    return a.area(t1)+b.area(t2)-d*(cps[1]-cps[0]).norm()/2;

}



lf carea(Polygon &p, Circle &c){

    lf ret=0;

    for(int i=0; i<p.n; i++){

        lf da = distance(p[i],c.p);

        lf db = distance(p[i+1],c.p);

        Segment s(p[i],p[i+1]);

        auto cps = cpoint(c,s);

        if (sgn(max(da,db)-c.r)<=0){

            ret+=det(p[i]-c.p,p[i+1]-c.p)/2;

        }else if(cps.empty()){

            lf t = acos(dot((p[i]-c.p).unit(),(p[i+1]-c.p).unit()));

            t *= sgn(det(p[i]-c.p,p[i+1]-c.p));

            ret+=c.area(t);

        }else{

            if (cps.size()==1) cps.push_back(cps[0]);

            ret+=det(cps[1]-c.p,cps[0]-c.p)/2;

            if (sgn(da-c.r)<=0) ret+=det(s.p-c.p,cps[1]-c.p)/2;

            else{

                lf t = acos(dot((s.p-c.p).unit(),(cps[1]-c.p).unit()));

                t *= sgn(det(s.p-c.p,cps[1]-c.p));

                ret+=c.area(t);

            }

            if (sgn(db-c.r)<=0) ret+=det(cps[0]-c.p,s.q-c.p)/2;

            else{

                lf t = acos(dot((cps[0]-c.p).unit(),(s.q-c.p).unit()));

                t *= sgn(det(cps[0]-c.p,s.q-c.p));

                ret+=c.area(t);

            }

        }

    }

    return ret;

}



//-------------------------------------------------

//--Popular Geometry Problems (depends on other)

//-------------------------------------------------



Circle enclose_all(vector<V> &ps){

    lf cx,cy;

    auto g = [&](lf x, lf y){

        lf ret=0;

        V v(x,y);

        for(int i=0; i<ps.size(); i++)

            chmax(ret,distance(v,ps[i]));

        return ret;

    };

    auto f = [&](lf x){

        int u=80;

        lf lo=ps[0].y, hi=ps[0].y;

        for(int i=0; i<ps.size(); i++){

            chmin(lo,ps[i].y);

            chmax(hi,ps[i].y);

        }

        while(u--){

            lf c1 = (lo*2+hi)/3;

            lf c2 = (lo+hi*2)/3;

            (g(x,c1)<g(x,c2))? hi=c2 : lo=c1;

        }

        cy = (hi+lo)/2;

        return g(x,cy);

    };

    int t=80;

    lf lo=ps[0].x, hi=ps[0].x;

    for(int i=0; i<ps.size(); i++){

        chmin(lo,ps[i].x);

        chmax(hi,ps[i].x);

    }

    while(t--){

        lf c1 = (lo*2+hi)/3;

        lf c2 = (lo+hi*2)/3;

        (f(c1)<f(c2))? hi=c2 : lo=c1;

    }

    cx = (hi+lo)/2;

    return Circle(V(cx,cy),g(cx,cy));

}





//-------------------------------------------------



int main(void)

{

    cin.tie(0);

    ios::sync_with_stdio(false);

    cout<<setp(12);

    int n; cin>>n;

    vector<V> ps;

    rep(i,n){

        int x,y; cin>>x>>y;

        ps.pb(V(x,y));

    }

    Circle c = enclose_all(ps);

    cout<<c.r<<"\n";

    return 0;

}