#include <iostream>
#include <iomanip>
#include <vector>
#include <cmath>

using namespace std;

constexpr long double EPS = 1e-10;

class Point{
    public: 
    long double x,y;
    Point(long double x = 0.0, long double y = 0.0): x(x), y(y) {}
    Point operator + (const Point &p) const { return Point(x+p.x, y+p.y); }
    Point operator - (const Point &p) const { return Point(x-p.x, y-p.y); }
    Point operator * (const long double &a) const { return Point(x*a, y*a); }
    Point operator / (const long double &a) const { return Point(x/a, y/a); }
    bool operator < (const Point &p) const { return (x != p.x ? x < p.x : y < p.y); }
    bool operator == (const Point &p) const { return fabsl(x - p.x) < EPS && fabsl(y - p.y) < EPS; }
    long double abs() const { return sqrt(norm()); }
    long double norm() const { return x*x + y*y; }
    long double dot(Point &p) const { return x*p.x + y*p.y; }
    long double cross(Point &p) const { return x*p.y - y*p.x; }   
};

typedef Point Vector;

vector<long double> GaussJordan(vector<vector<long double>> A){
    int n = A.size();
    int m = A[0].size();
    for(int i = 0; i < n; i++){
        int pivot = i;
        for(int j = i; j < n; j++) {
            if(abs(A[j][i]) > abs(A[pivot][i])) pivot = j;
        }
        swap(A[i], A[pivot]);
        if(abs(A[i][i]) < EPS) return {};
        for(int j = i + 1; j < m; j++) A[i][j] /= A[i][i];
        for(int j = 0; j < n; j++) {
            if(i != j) {
                for(int k = i + 1; k < m; k++) A[j][k] -= A[j][i] * A[i][k];
            }
        }
    }
    vector<long double> x(n);
    for(int i = 0; i < n; i++) x[i] = A[i].back();
    return x;
}

bool check(int n, vector<Point> &ps, long double r) {
    for(int i=0;i<n;++i) {
        for(int j=i+1;j<n;++j) {
            Point p1 = ps[i], p2 = ps[j];
            long double d = sqrt(r * r / (p2-p1).norm() - 0.25);
            if(r * r / (p2-p1).norm() - 0.25 < 0.0) return false;
            Point q = Point(
                (p1.x+p2.x)/2.0 + d*(p2.y-p1.y), 
                (p1.y+p2.y)/2.0 - d*(p2.x-p1.x)
            );
            bool ok = true;
            for(int k=0;k<n;++k) {
                if((ps[k]-q).abs() > r+EPS) {
                    ok = false;
                    break;
                }
            }
            if(ok) return true;
            ok = true;
            q = Point(
                (p1.x+p2.x)/2.0 - d*(p2.y-p1.y), 
                (p1.y+p2.y)/2.0 + d*(p2.x-p1.x)
            );
            for(int k=0;k<n;++k) {
                if((ps[k]-q).abs() > r+EPS) {
                    ok = false;
                    break;
                }
            }
            if(ok) return true;
        }
    }

    return false;
}

int main() {
    ios::sync_with_stdio(false); cin.tie(nullptr);
    int n;
    cin >> n;
    vector<Point> ps(n);
    for(int i=0;i<n;++i) {
        cin >> ps[i].y >> ps[i].x;
    }

    if(n == 2) {
        cout << setprecision(14) << fixed << (ps[1]-ps[0]).abs()/2.0 << endl;
        return 0;
    }

    long double r_low = 0.0, r_high = 100000.0;
    for(int i=0;i<100;++i) {
        long double r = (r_low + r_high) / 2.0;
        if(check(n, ps, r)) {
            r_high = r;
        } else {
            r_low = r;
        }
    }

    cout << setprecision(14) << fixed << r_high << endl;
}


Measured memory_bytes: 384