import java.math.*;
import java.util.*;
 
public class Main {
	static int[] uni;
	static int root(int a){
		if(uni[a]<0) return a;
		return uni[a] = root(uni[a]);
	}
	static boolean connect(int a,int b){
		a = root(a);
		b=root(b);
		if(a==b) return false;
		if(uni[a]>uni[b]){
			a ^= b;
			b^=a;
			a^=b;
		}
		uni[a]=uni[a]+uni[b];
		uni[b]=a;
		return true;
	}
	static boolean isConnect(int a,int b){
		return root(a)==root(b);
	}
	static int size(int a){
		return -uni[a];
	}
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] x = new int[n];
        int[] y = new int[n];
        uni=new int[n];
        Arrays.fill(uni, -1);
        if(n==0){
        	System.out.println(1);
        	return;
        }
        for(int i=0;i<n;i++){
        	x[i]=sc.nextInt();
        	y[i]=sc.nextInt();
        }
        for(int i=0;i<n-1;i++){
        	for(int j=i+1;j<n;j++){
        		if(Math.pow(x[i]-x[j], 2)+Math.pow(y[i]-y[j], 2)<=100){
        			connect(i,j);
        		}
        	}
        }
        double ans=0;
        for(int i=0;i<n-1;i++){
        	for(int j=i+1;j<n;j++){
        		if(isConnect(i,j)){
        			ans=Math.max(ans, Math.pow(x[i]-x[j], 2)+Math.pow(y[i]-y[j], 2));
        		}
        	}
        }
        System.out.println(Math.sqrt(ans)+2);
    }
}