import java.util.*;

public class Main {

    public static void main(String[] args){

        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        List<Point> points = new ArrayList<>();
        for(int i=0; i<n; i++) {
            points.add(new Point(sc.nextInt(), sc.nextInt()));
        }
        Circle circle = Sec.makeCircle(points);

        System.out.println(circle.r);
    }

}

final class Sec {

    public static Circle makeCircle(List<Point> points) {
        List<Point> shuffled = new ArrayList<>(points);
        Collections.shuffle(shuffled, new Random());
        Circle c = null;
        for (int i = 0; i < shuffled.size(); i++) {
            Point p = shuffled.get(i);
            if (c == null || !c.contains(p))
                c = makeCircleOnePoint(shuffled.subList(0, i + 1), p);
        }
        return c;
    }
    private static Circle makeCircleOnePoint(List<Point> points, Point p) {
        Circle c = new Circle(p, 0);
        for (int i = 0; i < points.size(); i++) {
            Point q = points.get(i);
            if (!c.contains(q)) {
                if (c.r == 0)
                    c = makeDiameter(p, q);
                else
                    c = makeCircleTwoPoints(points.subList(0, i + 1), p, q);
            }
        }
        return c;
    }
    private static Circle makeCircleTwoPoints(List<Point> points, Point p, Point q) {
        Circle circ = makeDiameter(p, q);
        Circle left  = null;
        Circle right = null;
        Point pq = q.subtract(p);
        for (Point r : points) {
            if (circ.contains(r))
                continue;
            double cross = pq.cross(r.subtract(p));
            Circle c = makeCircumcircle(p, q, r);
            if (c == null)
                continue;
            else if (cross > 0 && (left == null || pq.cross(c.c.subtract(p)) > pq.cross(left.c.subtract(p))))
                left = c;
            else if (cross < 0 && (right == null || pq.cross(c.c.subtract(p)) < pq.cross(right.c.subtract(p))))
                right = c;
        }

        if (left == null && right == null)
            return circ;
        else if (left == null)
            return right;
        else if (right == null)
            return left;
        else
            return left.r <= right.r ? left : right;
    }


    static Circle makeDiameter(Point a, Point b) {
        Point c = new Point((a.x + b.x) / 2, (a.y + b.y) / 2);
        return new Circle(c, Math.max(c.distance(a), c.distance(b)));
    }


    static Circle makeCircumcircle(Point a, Point b, Point c) {
        // Mathematical algorithm from Wikipedia: Circumscribed circle
        double ox = (Math.min(Math.min(a.x, b.x), c.x) + Math.max(Math.min(a.x, b.x), c.x)) / 2;
        double oy = (Math.min(Math.min(a.y, b.y), c.y) + Math.max(Math.min(a.y, b.y), c.y)) / 2;
        double ax = a.x - ox,  ay = a.y - oy;
        double bx = b.x - ox,  by = b.y - oy;
        double cx = c.x - ox,  cy = c.y - oy;
        double d = (ax * (by - cy) + bx * (cy - ay) + cx * (ay - by)) * 2;
        if (d == 0)
            return null;
        double x = ((ax*ax + ay*ay) * (by - cy) + (bx*bx + by*by) * (cy - ay) + (cx*cx + cy*cy) * (ay - by)) / d;
        double y = ((ax*ax + ay*ay) * (cx - bx) + (bx*bx + by*by) * (ax - cx) + (cx*cx + cy*cy) * (bx - ax)) / d;
        Point p = new Point(ox + x, oy + y);
        double r = Math.max(Math.max(p.distance(a), p.distance(b)), p.distance(c));
        return new Circle(p, r);
    }

}

final class Circle {

    private static final double MULTIPLICATIVE_EPSILON = 1 + 1e-14;
    public final Point c;
    public final double r;


    public Circle(Point c, double r) {
        this.c = c;
        this.r = r;
    }
    public boolean contains(Point p) {
        return c.distance(p) <= r * MULTIPLICATIVE_EPSILON;
    }
    public boolean contains(Collection<Point> ps) {
        for (Point p : ps) {
            if (!contains(p))
                return false;
        }
        return true;
    }
}

final class Point {

    public final double x;
    public final double y;

    public Point(double x, double y) {
        this.x = x;
        this.y = y;
    }

    public Point subtract(Point p) {
        return new Point(x - p.x, y - p.y);
    }

    public double distance(Point p) {
        return Math.hypot(x - p.x, y - p.y);
    }

    public double cross(Point p) {
        return x * p.y - y * p.x;
    }
}


Measured memory_bytes: 21972