#include <bits/stdc++.h>
using namespace std;
int group[1000];
int calc(int x,int y){
	return x*x+y*y;
}
int find(int x){
	if(group[x]==x)	return x;
	group[x]=find(group[x]);
	return group[x];
}
void merge(int i,int j){
	int a=find(group[i]);
	group[a]=find(group[j]);
}
int main(){
	for(int i=0;i<1000;i++)	group[i]=i;
	int n;	cin>>n;
	if(n==0){
		cout<<1<<endl;
		return 0;
	}
	int x[n],y[n];
	for(int i=0;i<n;i++)	cin>>x[i]>>y[i];
	for(int i=0;i<n;i++){
		for(int j=0;j<n;j++){
			if(calc(x[i]-x[j],y[i]-y[j])<=100){
				merge(i,j);
			}
		}
	}
	for(int i=0;i<n;i++)	group[i]=find(group[i]);
	int longest=0;
	for(int i=0;i<n;i++){
		for(int j=0;j<n;j++){
			if(group[i]==group[j]){
				longest=max(longest,calc(x[i]-x[j],y[i]-y[j]));
			}
		}
	}
	printf("%.15lf\n",(double)sqrt(longest)+2);
	return 0;
}