package yukicoder; import java.util.Scanner; public class No_94 { public static void main(String[] args) { Scanner sc = new Scanner(System.in); int N = sc.nextInt(); if(N == 0 ){ System.out.println(1); return; } int[] x = new int[N]; int[] y = new int[N]; for(int i = 0; i < N; i++){ x[i] = sc.nextInt(); y[i] = sc.nextInt(); } double tmp = Math.sqrt(Math.pow(x[0] - x[1], 2) + Math.pow(y[0] - y[1], 2)); for(int i = 0; i < N - 1; i++){ for(int j = i + 1; j < N; j++){ double d = Math.sqrt(Math.pow(x[i] - x[j], 2) + Math.pow(y[i] - y[j], 2)); if(d > tmp){ tmp = d; } } } if(N > 2 && tmp > 10.0){ System.out.println(2); }else{ double ans = tmp + 2.0; System.out.println(ans); } } }