#include <iostream>
#include <algorithm>
using namespace std;

class Point {
public:
  int x, y;
  Point(void) {}
  Point(int _x, int _y) { x = _x; y = _y; }
  bool operator==(const Point& other) const { return x == other.x && y == other.y; }
  int distdist(const Point& other) const { return (x - other.x) * (x - other.x) + (y - other.y) * (y - other.y); }
};

int cost[1010][1010];
bool route[1010][1010];
const int inf = 987654321;

int main(void) {
  int n; scanf("%d", &n);
  vector<Point> v(n);
  for(int i=0; i<n; i++) {
    int x, y; scanf("%d%d", &x, &y);
    v[i] = Point(x, y);
  }
  for(int i=0; i<n-1; i++) {
    for(int j=i+1; j<n; j++) {
      int dd = v[i].distdist(v[j]);
      cost[i][j] = dd;
      cost[j][i] = dd;
      if(dd > 10 * 10) { continue; }
      route[i][j] = true;
      route[j][i] = true;
    }
  }
  for(int k=0; k<n; k++) {
    for(int i=0; i<n; i++) {
      for(int j=0; j<n; j++) {
        route[i][j] = route[i][j] || (route[i][k] && route[k][j]);
      }
    }
  }
  int res = 0;
  for(int i=0; i<n-1; i++) {
    for(int j=i+1; j<n; j++) {
      if(!route[i][j]) { continue; }
      res = max(res, cost[i][j]);
    }
  }
  printf("%lf\n",  sqrt(res) + 1 + (n>0));
  return 0;
}