#include <bits/stdc++.h>
#define FOR(i,a,b) for (int i=(a);i<(b);i++)
#define FORR(i,a,b) for (int i=(a);i>=(b);i--)
#define pb push_back
#define pcnt __builtin_popcount
#define show(x) cout<<#x<<" = "<<x<<endl;
#define maxs(x,y) x = max(x,y)
#define mins(x,y) x = min(x,y)
#define fi first
#define se second
#define rng(a) a.begin(),a.end()
#define each(it,c) for(__typeof((c).begin()) it=(c).begin();it!=(c).end();it++)
#define sz(x) (int)(x).size()
#define mp make_pair

using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<pii> vpii;
typedef set<int> si;
typedef pair<ll,ll> pll;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<pll> vpll;
typedef set<ll> sl;
template<typename T>string join(vector<T>&v)
{stringstream s;FOR(i,0,sz(v))s<<' '<<v[i];return s.str().substr(1);}
ll gcd(ll a,ll b){if(a>b)swap(a,b);for(;a>0;b%=a,swap(a,b));return b;}
int modpow(ll a,ll n,int m){if(a==0)return a;ll p=1;for(;n>0;n/=2,a=a*a%m)if(n&1)p=p*a%m;return(int)p;}
void dout(double d){printf("%.12f\n",d);}

const int iinf = 1e9;
const ll linf = 1e18;
const int mod = 1e9+7;
const double pi = acos(-1);
const double eps = 1e-10;

int n;
pii c[120000];
map<pii, vi> m;
vpii vd;
inline bool between(int a, int b){
  return (c[a].fi - c[b].fi) * (c[a].fi - c[b].fi) + (c[a].se - c[b].se) * (c[a].se - c[b].se) <= 100;
}
inline ll r(int a, int b){
  return (c[a].fi - c[b].fi) * (c[a].fi - c[b].fi) + (c[a].se - c[b].se) * (c[a].se - c[b].se);
}

struct UnionFind{
  vi p;
  vi _next, _last;
  void init(int n){
    p.resize(n);
    _next.resize(n);
    _last.resize(n);
    FOR(i, 0, n){
      p[i] = -1;
      _next[i] = -1;
      _last[i] = i;
    }
  }
  int find(int a){
    if(p[a] < 0) return a;
    p[a] = find(p[a]);
    return p[a];
  }
  void merge(int a, int b){
    a = find(a);
    b = find(b);
    if(a == b) return;
    if(p[a] < p[b]) swap(a, b);
    p[a] += p[b];
    p[b] = a;
    _next[_last[a]] = b;
    _last[a] = _last[b];
  }
  void get_list(int a, vi&v){
    v.clear();
    int d = find(a);
    while(d >= 0){
      v.pb(d);
      d = _next[d];
    }
  }
};
UnionFind uf;

main(){
  cin.tie(0);
  ios::sync_with_stdio(false);
  cin >> n;
  if(n == 0){
    cout << 1 << endl;
    return 0;
  }
  FOR(i, 0, n){
    int x, y;
    cin >> x >> y;
    x += 10000;
    y += 10000;
    c[i] = mp(x, y);
    m[mp(x/10, y/10)].pb(i);
  }
  vd.pb(mp( 1, 1));
  vd.pb(mp( 0, 1));
  vd.pb(mp(-1, 1));
  vd.pb(mp( 1, 0));
  vd.pb(mp( 0, 0));
  uf.init(n);
  each(itr, m){
    int x = itr->fi.fi, y = itr->fi.se;
    each(itr2, vd){
      each(itr3, itr->se){
        each(itr4, m[mp(x+itr2->fi, y+itr2->se)]){
          if(*itr3 != *itr4 && between(*itr3, *itr4)) uf.merge(*itr3, *itr4);
        }
      }
    }
  }
  ll ma = 0;
  vi v;
  FOR(i, 0, n){
    if(uf.find(i) != i)continue;
    uf.get_list(i, v);
    each(itr1, v){
      each(itr2, v){
        if(*itr1 == *itr2) break;
        maxs(ma, r(*itr1, *itr2));
      }
    }
  }
  dout(sqrt((double)ma) + 2.);
  return 0;
}