/*
 *   Copyright (c) 2024 Emon Thakur
 *   All rights reserved.
 */
#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
using minheap = priority_queue<long long, vector<long long>, greater<long long>>;
typedef tree<int, null_type, greater_equal<int>, rb_tree_tag, tree_order_statistics_node_update> pbds; // find_by_order, order_of_key

#define ll long long
#define ld long double
#define MOD 1000000007
#define pie 2*(acos(0.0))
#define yes cout<<"YES\n"
#define no cout<<"NO\n"
#define pb push_back
#define endl '\n'
#define lcm(a,b) (a*b)/(__gcd<ll>(a,b))
#define print(v) for(auto e:v) cout<<e<<" "; cout<<endl;
#define printp(v) for(auto e:v) cout<<e.first<<" "<<e.second<<endl;
#define srt(v) sort(v.begin(),v.end())
#define rsrt(v) sort(v.rbegin(),v.rend())
#define life_is_a_race ios::sync_with_stdio(false); cin.tie(nullptr);

void solve(int tc)
{
    //cout<<"Case "<<tc<<": ";
    int n; cin >> n;
    vector<pair<ld,ld>> v(n);
    for(int i=0;i<n;i++)
    {
        cin>>v[i].first >> v[i].second;
    }
    ld ans  = 1000000000,r,x,y,d;
    if(n == 1) {
        ans = 0;
    }
    for(int i=0;i<n;i++)
    {
        for(int j=i+1;j<n;j++)
        {
            x = (v[i].first+v[j].first)/2.0L;
            y = (v[i].second+v[j].second)/2.0L;
            r = sqrtl((v[i].first-v[j].first)*(v[i].first-v[j].first)+(v[i].second-v[j].second)*(v[i].second-v[j].second)) / 2.0L;
            bool ok = true;
            for(int k=0;k<n;k++)
            {
                if(k==i || k==j) continue;
                d = sqrtl((x-v[k].first)*(x-v[k].first) + (y-v[k].second)*(y-v[k].second));
                if(d > r) 
                {
                    ok = false;
                    break;
                }
            }
            if(ok) ans = min(ans , r);
        }
    }
    cout<<fixed<<setprecision(18)<<ans;
}
int main()
{
    life_is_a_race
    int t=1; 
    //cin>>t;
    for(int i=1;i<=t;i++) solve(i);
}