//#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
#define rep(i, n) for(int i=0; i<n; ++i)
using namespace std;

const double EPS = 1e-10;
double add(double a, double b) {
    if(abs(a+b) < EPS*(abs(a)+abs(b))) return 0;
    return a+b;
}
struct Vector {
    double x, y;
    Vector(double x=0, double y=0):x(x), y(y) {}
    Vector operator+(Vector v) {return Vector(add(x, v.x), add(y, v.y));}
    Vector operator-(Vector v) {return Vector(add(x, -v.x), add(y, -v.y));}
    Vector operator*(double d) {return Vector(x*d, y*d);}
    Vector operator/(double d) {return Vector(x/d, y/d);}
    double dot(Vector v) {return add(x*v.x, y*v.y);}
    double cross(Vector v) {return add(x*v.y, -y*v.x);}
    Vector rotate(double theta) {return Vector(add(x*cos(theta), -y*sin(theta)), add(x*sin(theta), y*cos(theta)));}
};
struct Circle {
    double r;
    Vector c;
    Circle() {}
    Circle(double r, Vector c):r(r), c(c) {}
};
istream &operator>>(istream &is, Vector &v) {return is >> v.x >> v.y;}
ostream &operator<<(ostream &os, const Vector &v) {return os << v.x << ' ' << v.y;}
double sqdist(Vector v, Vector u) {return (v-u).dot(v-u);}
//線分v2-v1上にあるか
bool on_seg(Vector &v1,Vector &v2, const Vector &p) {
    return (v1-p).cross(v2-p) == 0 && (v1-p).dot(v2-p) <= 0;
}
//v1-v2とu1-u2の交点
Vector intersection(Vector &v1,Vector &v2,Vector &u1,Vector &u2) {
    assert((v1-v2).cross(u1-u2)); //2直線が平行だとだめ
    return v1 + (v2-v1)*((u2-u1).cross(u1-v1)/(u2-u1).cross(v2-v1));
}
//p2-p1へのQの投影
Vector projection(Vector &p1,Vector &p2,Vector &Q) {
    return p1+(p2-p1)*(Q-p1).dot(p2-p1)/sqdist(p1, p2);
}
//p1-p2を軸としたQの線対称移動
Vector reflection(Vector &p1,Vector &p2,Vector &Q) {
    return projection(p1, p2, Q)*2-Q;
}
//2円が交わりを持つか
bool com_cir(Circle &a, Circle &b) {
    return add((a.r+b.r)*(a.r+b.r), - sqdist(a.c, b.c)) >= 0;
}
//円aが円bを含んでいるか
bool over_cir(Circle &a, Circle &b) {
    return add(a.r - sqrt(sqdist(a.c, b.c)), -b.r) >= 0;
}
//円aが含むか
bool on_cir(Circle &a, Vector &p) {
    return add(sqdist(a.c, p), -a.r*a.r) <= 0;
}
bool cmp_x(const Vector &v, const Vector &u) {
    if(v.x != u.x) return v.x < u.x;
    return v.y < u.y;
}
bool cmp_y(const Vector &v, const Vector &u) {
    if(v.y != u.y) return v.y < u.y;
    return v.x < u.x;
}
//凸包 頂点数nの頂点集合vv
vector<Vector> convex_hull(vector<Vector> &vv, int n) {
    sort(vv.begin(), vv.end(), cmp_x);
    int k = 0;
    vector<Vector> res(n*2);
    for(int i = 0; i < n; i++) {
        while(k > 1 && (res[k-1]-res[k-2]).cross(vv[i]-res[k-1]) <= 0) k--;
        res[k++] = vv[i];
    }
    for(int i = n-2, t = k; i >= 0; i--) {
        while(k > t && (res[k-1]-res[k-2]).cross(vv[i]-res[k-1]) <= 0) k--;
        res[k++] = vv[i];
    }
    res.resize(k-1);
    return res;
}
//点と線の距離
double distpl(Vector &p0, Vector &p1, Vector &Q) {
    Vector pp = projection(p0, p1, Q);
    return sqrt(sqdist(pp, Q));
}
//線分と線分の距離
double distss(Vector &p0, Vector &p1, Vector &p2, Vector &p3) {
    if((p0-p1).cross(p2-p3) != 0) {
        Vector p = intersection(p0, p1, p2, p3);
        if(on_seg(p0, p1, p) and on_seg(p2, p3, p)) {
            return 0.0;
        }
    }
    double res = min({sqdist(p0, p2), sqdist(p0, p3), sqdist(p1, p2), sqdist(p1, p3)});
    Vector pp0, pp1, pp2, pp3;
    pp2 = projection(p0, p1, p2);
    pp3 = projection(p0, p1, p3);
    pp0 = projection(p2, p3, p0);
    pp1 = projection(p2, p3, p1);
    if(on_seg(p0, p1, pp2)) res = min(res, sqdist(pp2, p2));
    if(on_seg(p0, p1, pp3)) res = min(res, sqdist(pp3, p3));
    if(on_seg(p2, p3, pp0)) res = min(res, sqdist(pp0, p0));
    if(on_seg(p2, p3, pp1)) res = min(res, sqdist(pp1, p1));
    res = sqrt(res);
    return res;
}


bool inter_cir(Circle &a, Circle &b, Vector &p1, Vector &p2) {
    if(!com_cir(a, b)) return false;
    Vector c = (a.c+b.c)/2;
    p1 = (b.c-c).rotate(M_PI/2);
    double h = sqrt(add(a.r*b.r, -sqdist(p1, Vector())));
    p1 = p1/sqrt(sqdist(p1, Vector()))*h;
    p1 = p1+c;
    p2 = reflection(a.c, b.c, p1);
    return true;
}

signed main() {
    cout << fixed << setprecision(13);
    int n;
    cin >> n;
    vector<Vector> v(n);
    rep(i, n) cin >> v[i];

    double a, b, c;
    a = 0; c = 1e5;
    rep(iii, 100) {
        b = (a+c)/2;
        vector<Circle> cir(n);
        rep(i, n) {
            cir[i] = Circle(b, v[i]);
        }
        bool ok = false;
        rep(i, n) rep(j, i) {
            Vector p, q;
            if(inter_cir(cir[i], cir[j], p, q)) {
                bool xp = true, xq = true;
                rep(k, n) {
                    if(!on_cir(cir[k], p)) xp = false;
                    if(!on_cir(cir[k], q)) xq = false;
                }
                if(xp or xq) {
                    ok = true;
                    break;
                }
            }
        }
        if(ok) {
            c = b;
        } else {
            a = b;
        }
    }

    cout << c << endl;
}

Measured memory_bytes: 3804