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

#define int long long
#define itn int
#define For(i, a, b) for (int i = (a); i <= static_cast<int>(b); i++)
#define Forr(i, a, b) for (int i = (a); i >= static_cast<int>(b); i--)
#define rep(i, n) For(i, 0, n - 1)
#define repall(i, arr) for (auto& i : (arr))
#define all(x) (x).begin(), (x).end()
#define pb push_back
#define dump(x) cerr << #x << " = " << (x) << '\n'
#define dump2(x, y) \
    cerr << #x << " = " << (x) << " " << #y << " = " << (y) << '\n'
#define SZ(x) ((int)(x).size())
#define bit(n) (1LL << (n))
constexpr int MOD = 1e9 + 7;

template <typename T>
using pq = priority_queue<T>;
template <typename T>
using pqr = priority_queue<T, vector<T>, greater<T>>;
const int INF = LLONG_MAX / 2;
using P = pair<int, int>;
using vec = vector<int>;
template <typename T>
using mat = vector<vector<T>>;

// clang-format off
template <typename T1, typename T2>
ostream& operator<<(ostream& stream, const pair<T1, T2>& p) { return stream << p.first << "," << p.second; }
template <typename T>
void print(const vector<T> vec) { rep (i, vec.size() - 1) cout << vec[i] << ' '; cout << vec[vec.size() - 1] << '\n'; }
template <typename Arg>
void print(const Arg arg) { cout << arg << '\n'; }
template <typename Head, typename... Args>
void print(const Head head, const Args... args) { cout << head << " "; print(args...); }
template <typename T, typename U>
void init(vector<T>& v, vector<U>& w) { rep (i, v.size()) cin >> v[i] >> w[i]; }
template <typename T>
void init(vector<T>& v) { rep (i, v.size()) cin >> v[i]; }
template <typename T>
T sum_(vector<T> vec, T init = 0) { return std::accumulate(all(vec), T(init)); }
template<typename T>
bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } return false; }
template<typename T>
bool chmin(T& a, const T& b) { if (a > b) { a = b; return true; } return false; }
template <typename T>
int index(const T& vec, const typename T::iterator it) { return distance(vec.begin(), it); }
template <typename T = int>
mat<T> mmat(int n, int m=0) { return mat<T>(n, vector<T>(m)); }
template <typename T = int>
vector<T> ivec(int n) { vector<T> v(n); init(v); return v; }
// clang-format on

void yn(bool tf) { print(tf ? "Yes" : "No"); }
void YN(bool tf) { print(tf ? "YES" : "NO"); }

int gcd(int a, int b) { return b ? gcd(b, a % b) : a; }
// -------------------------------------------------------------------
// sort 1 2 3 4
// pqr 1 2 3 must impl >
vector<double> x, y;

void calc(int i, int j, int k, double& rx, double& ry, double& r) {
    double xue = (x[i] * x[i] + y[i] * y[i]) * (y[j] - y[k]) +
                 (x[j] * x[j] + y[j] * y[j]) * (y[k] - y[i]) +
                 (x[k] * x[k] + y[k] * y[k]) * (y[i] - y[j]);
    double xsita = 2 * (x[i] * (y[j] - y[k]) - y[i] * (x[j] - x[k]) +
                        x[j] * y[k] - x[k] * y[j]);
    rx = xue / xsita;

    double yue = (x[i] * x[i] + y[i] * y[i]) * (x[k] - x[j]) +
                 (x[j] * x[j] + y[j] * y[j]) * (x[i] - x[k]) +
                 (x[k] * x[k] + y[k] * y[k]) * (x[j] - x[i]);
    double ysita = 2 * (x[i] * (y[j] - y[k]) - y[i] * (x[j] - x[k]) +
                        x[j] * y[k] - x[k] * y[j]);
    ry = yue / ysita;
    r = sqrt((rx - x[i]) * (rx - x[i]) + (ry - y[i]) * (ry - y[i]));
}

signed main() {
    cin.tie(0), cout.tie(0), ios::sync_with_stdio(false);
    int n;
    cin >> n;
    x = vector<double>(n);
    y = vector<double>(n);
    init(x, y);

    if (n == 2) {
        double r = sqrt((x[0] - x[1]) * (x[0] - x[1]) +
                        (y[0] - y[1]) * (y[0] - y[1])) /
                   2;
        cout << setprecision(10) << r << endl;
        return 0;
    }
    double ans = 1e10;

    For(i, 0, n - 1) {
        For(j, i + 1, n - 1) {
            For(k, j + 1, n - 1) {
                double rx, ry, r;
                calc(i, j, k, rx, ry, r);

                if (abs(rx) > 1e10 or abs(ry) > 1e10) continue;

                bool ok = true;
                For(u, 0, n - 1) {
                    if (sqrt((x[u] - rx) * (x[u] - rx) +
                             (y[u] - ry) * (y[u] - ry)) > r + 1e-5) {
                        ok = false;
                        break;
                    }
                }
                if (ok) chmin(ans, r);
            }
        }
    }

    For(i, 0, n - 1) {
        For(j, i + 1, n - 1) {
            double rx, ry, r;
            rx = (x[i] + x[j]) / 2;
            ry = (y[i] + y[j]) / 2;
            r = sqrt((rx - x[i]) * (rx - x[i]) + (ry - y[i]) * (ry - y[i]));

            bool ok = true;
            For(u, 0, n - 1) {
                if (sqrt((x[u] - rx) * (x[u] - rx) +
                         (y[u] - ry) * (y[u] - ry)) > r + 1e-5) {
                    ok = false;
                    break;
                }
            }
            if (ok) chmin(ans, r);
        }
    }
    cout << setprecision(10) << ans << endl;

    return 0;
}


Measured memory_bytes: 256