#include <iostream>
#include <algorithm>
#include <vector>
#include <cstdio>
#include <cmath>
using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)

int main(void){
	int n; cin >> n;
	if(n == 0){
		printf("0\n"); return 0;
	}
	vector<int> x(n);
	vector<int> y(n);
	rep(i, n) cin >> x[i] >> y[i];
	double ans = 0;
	for (int i = 0; i < n; ++i){
		for (int j = i + 1; j < n; ++j){
			int now = (x[j] - x[i]) * (x[j] - x[i])
					  + (y[j] - y[i]) * (y[j] - y[i]);
			if(now <= 100) ans = now;
		}
	}
	if(ans == 0){
		printf("2\n"); return 0;
	}
	// printf("%f\n", ans);
	printf("%f\n", sqrt(ans) + 2.0);
	return 0;
}