import java.util.*;
import java.io.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        if (n == 0) {
            System.out.println(1);
            return;
        }
        Point[] poins = new Point[n];
        for (int i = 0; i < n; i++) {
            poins[i] = new Point(sc.nextInt(), sc.nextInt());
        }
        UnionFindTree uft = new UnionFindTree(n);
        for (int i = 0; i < n; i++) {
            for (int j = i + 1; j < n; j++) {
                if (poins[i].getDistance(poins[j]) <= 100) {
                    uft.unite(i, j);
                }
            }
        }
        int max = 0;
        for (int i = 0; i < n; i++) {
            for (int j = i + 1; j < n; j++) {
                if (uft.same(i, j)) {
                    max = Math.max(max, poins[i].getDistance(poins[j]));
                }
            }
        }
        System.out.println(Math.sqrt(max) + 2);
    }
    
    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(y)] = find(x);
            }
        }
    }
    
    static class Point {
        int x;
        int y;
        
        public Point(int x, int y) {
            this.x = x;
            this.y = y;
        }
        
        public int getDistance(Point p) {
            return (x - p.x) * (x - p.x) + (y - p.y) * (y - p.y);
        }
    }
    
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public String nextLine() throws Exception {
        return br.readLine();
    }
    
    public String next() throws Exception {
        if (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
}