import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        if (n == 0) {
            System.out.println(1);
            return;
        }
        Point[] points = new Point[n];
        for (int i = 0; i < n; i++) {
            points[i] = new Point(sc.nextInt(), sc.nextInt());
        }
        UnionFindTree uft = new UnionFindTree(n);
        for (int i = 0; i < n - 1; i++) {
            for (int j = i + 1; j < n; j++) {
                if (uft.same(i, j)) {
                    continue;
                }
                if (points[i].getDist(points[j]) <= 100) {
                    uft.unite(i, j);
                }
            }
        }
        HashMap<Integer, ArrayList<Point>> map = new HashMap<>();
        for (int i = 0; i < n; i++) {
            int key = uft.find(i);
            if (!map.containsKey(key)) {
                map.put(key, new ArrayList<>());
            }
            map.get(key).add(points[i]);
        }
        int max = 0;
        for (ArrayList<Point> list : map.values()) {
            for (int i = 0; i < list.size() - 1; i++) {
                for (int j = i + 1; j < list.size(); j++) {
                    max = Math.max(max, list.get(i).getDist(list.get(j)));
                }
            }
        }
        System.out.println(Math.sqrt(max) + 2);
    }
    
    static class Point {
        int x;
        int y;
        
        public Point(int x, int y) {
            this.x = x;
            this.y = y;
        }
        
        public int getDist(Point another) {
            return (x - another.x) * (x - another.x) + (y - another.y) * (y - another.y);
        }
    }
    
    static class UnionFindTree {
        int[] parents;
        
        public UnionFindTree(int size) {
            parents = new int[size];
            for (int i = 0; i < size; i++) {
                parents[i] = i;
            }
        }
        
        public int find(int x) {
            if (x == parents[x]) {
                return x;
            } else {
                return parents[x] = find(parents[x]);
            }
        }
        
        public boolean same(int x, int y) {
            return find(x) == find(y);
        }
        
        public void unite(int x, int y) {
            if (!same(x, y)) {
                parents[find(x)] = find(y);
            }
        }
    }
}