#include <bits/stdc++.h>
using namespace std;
static const long long INF = 1 << 29;
bool compare_by_b(pair<int, int> a, pair<int, int> b) {
  if (a.second != b.second) {
    return a.second < b.second;
  } else {
    return a.first < b.first;
  }
}
long double dist(pair<long long, long long> r1, pair<long long, long long> r2) {
  return pow(pow((long double)r1.first - r2.first, 2) +
                 pow((long double)r1.second - r2.second, 2),
             0.5);
}
int main() {
  int N;
  cin >> N;
  vector<pair<long long, long long> > r(N);
  for (long long i = 0; i < (long long)(N); i++)
    cin >> r.at(i).first >> r.at(i).second;
  long double ans = 0;
  for (pair<long long, long long> i : r) {
    for (pair<long long, long long> j : r) {
      if (dist(i, j) > ans) ans = dist(i, j);
    }
  }
  cout << fixed << setprecision(20) << (long double)ans * 0.5 << endl;
  return 0;
}
