#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include "debug.h"
#else
#define dump(...)
#endif
#define endl "\n"
#define ll long long
#define int ll
#define float double
#define FOR(i, a, b) for (int i = (int)(a); i < (int)(b); i++)
#define REP(i, x) for (int i = 0; i < (int)(x); i++)
#define REPS(i, x) for (int i = 1; i <= (int)(x); i++)
#define RREP(i, x) for (int i = ((int)(x)-1); i >= 0; i--)
#define RREPS(i, x) for (int i = ((int)(x)); i > 0; i--)
#define INF (1 << 30 - 1)
#define LLINF (1LL << 60)
#define vi vector<int>
#define vvi vector<vector<int>>
#define pi pair<int, int>
#define ALL(a) (a).begin(), (a).end()
#define BIT(n) (1LL << (n))
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end()) //sortしてからつかうこと
constexpr ll MOD = 1e9 + 7;
int dx[8] = {1, 0, -1, 0, 1, 1, -1, -1};
int dy[8] = {0, 1, 0, -1, 1, -1, 1, -1};
ll A, B, C, D, E, F, G, H, N, M, L, K, P, Q, R, W, X, Y, Z;
string S, T;
ll ans = 0;

template <typename T>
istream &operator>>(istream &is, vector<T> &vec) {
    for (T &x : vec)
        is >> x;
    return is;
}

template <typename T>
class Vec3 {
public:
    T x = 0, y = 0, z = 0;
    Vec3() {}
    Vec3(T x, T y, T z) : x(x), y(y), z(z) {}

    bool operator==(const Vec3 &other) const {
        return x == other.x && y == other.y && z == other.z;
    }
    bool operator!=(const Vec3 &other) const {
        return x != other.x || y != other.y || z != other.z;
    }

    Vec3 &operator+=(const Vec3 &other) {
        x += other.x;
        y += other.y;
        z += other.z;
        return *this;
    }

    Vec3 &operator-=(const Vec3 &other) {
        x -= other.x;
        y -= other.y;
        z -= other.z;
        return *this;
    }

    Vec3 &operator*=(const T k) {
        x *= k;
        y *= k;
        z *= k;
        return *this;
    }

    Vec3 &operator/=(const T k) {
        x /= k;
        y /= k;
        z /= k;
        return *this;
    }

    Vec3 &operator=(const Vec3 &other) {
        x = other.x;
        y = other.y;
        z = other.z;
        return *this;
    }

    Vec3 operator+(const Vec3 &other) const {
        Vec3 res = *this;
        return res += other;
    }

    Vec3 operator-(const Vec3 &other) const {
        Vec3 res = *this;
        return res -= other;
    }

    Vec3 operator*(const T k) const {
        Vec3 res = *this;
        return res *= k;
    }

    Vec3 operator/(const T k) const {
        Vec3 res = *this;
        return res /= k;
    }

    T norm() {
        return sqrt(x * x + y * y + z * z);
    }

    T squared_norm() {
        return (x * x + y * y + z * z);
    }

    T dot(const Vec3 &other) const {
        return x * other.x + y * other.y + z * other.z;
    }

    Vec3 cross(const Vec3 &other) {
        Vec3 res;
        res.x = y * other.z - other.y * z;
        res.y = z * other.x - other.z * x;
        res.z = x * other.y - other.x * y;
        return res;
    }

    void normalize() {
        T n = this->norm();
        *this /= n;
    }
};

template <typename T>
Vec3<T> operator*(const T k, Vec3<T> &v) {
    Vec3<T> res = v;
    return res *= k;
}

template <typename T>
Vec3<T> operator/(const T k, Vec3<T> &v) {
    Vec3<T> res = v;
    return res /= k;
}

using Vec3f = Vec3<float>;
using Vec3d = Vec3<double>;

class SmallestEnclosingDisc {
public:
    vector<Vec3d> points;
    void addPoint(double x, double y) {
        points.push_back({x, y, 0});
    }
    pair<Vec3d, double> circle3pts(Vec3d &a, Vec3d &b, Vec3d &c) {
        double A = (b - c).squared_norm();
        double B = (c - a).squared_norm();
        double C = (a - b).squared_norm();
        double S = abs((c - a).cross(b - a).z);
        Vec3d center = (A * (B + C - A) * a + B * (C + A - B) * b + C * (A + B - C) * c) / (4 * S * S);
        double radius = sqrt(A * B * C) / (2.0 * S);
        //double radius = (a - center).norm();
        return {center, radius};
    }

    pair<Vec3d, double> circle2pts(Vec3d &a, Vec3d &b) {
        Vec3d center = (a + b) / 2.0;
        double radius = (a - b).norm() / 2.0;
        return {center, radius};
    }

    pair<Vec3d, double> calc() {
        random_device seed_gen;
        mt19937 engine(seed_gen());
        shuffle(points.begin(), points.end(), engine);
        vector<int> R;
        return calc(points.size(), R);
    }

    pair<Vec3d, double> calc(int sizeP, vector<int> R, int indexP_R = 0) {
        if (sizeP == 2) {
            for (int i = indexP_R; i < points.size(); i++) {
                R.push_back(i);
            }
            Vec3d a, b;
            a = points[R[0]];
            b = points[R[1]];
            return circle2pts(a, b);
        } else if (R.size() >= 3) {
            Vec3d a, b, c;
            a = points[R[0]];
            b = points[R[1]];
            c = points[R[2]];
            return circle3pts(a, b, c);
        } else {
            auto c = calc(sizeP - 1, R, indexP_R + 1);
            if ((c.first - points[indexP_R]).norm() < c.second) {
                return c;
            } else {
                R.push_back(indexP_R);
                return calc(sizeP, R, indexP_R + 1);
            }
        }
    }
};

signed main() {
    cin >> N;
    SmallestEnclosingDisc sed;
    for (int i = 0; i < N; i++) {
        double x, y;
        cin >> x >> y;
        sed.addPoint(x, y);
    }
    auto c = sed.calc();
    cout << setprecision(10) << c.second << endl;
}

Measured memory_bytes: 256