/* Aa^~ kokoro ga pyonpyon suru n jaa^~
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*/
#include<bits/stdc++.h>
using namespace std;
#ifndef ONLINE_JUDGE
#define dbg(x...) do { cout << "\033[32;1m " << #x << " -> "; err(x); } while (0)
void err() { cout << "\033[39;0m" << endl; }
template<template<typename...> class T, typename t, typename... A>
void err(T<t> a, A... x) { for (auto v: a) cout << v << ' '; err(x...); }
template<typename T, typename... A>
void err(T a, A... x) { cout << a << ' '; err(x...); }
#else
#define dbg(...)
#endif
typedef long long ll;
typedef vector<int> vi;
template<class T> using vc=vector<T>;
template<class T> using vvc=vc<vc<T>>;
template<class T> void mkuni(vector<T>&v)
{
    sort(v.begin(),v.end());
    v.erase(unique(v.begin(),v.end()),v.end());
}
ll rand_int(ll l, ll r) //[l, r]
{
    static mt19937_64 gen(chrono::steady_clock::now().time_since_epoch().count());
    return uniform_int_distribution<ll>(l, r)(gen);
}
template<class T>
void print(T x,int suc=1)
{
    cout<<x;
    if(suc==1) cout<<'\n';
    else cout<<' ';
}
template<class T>
void print(const vector<T>&v,int suc=1)
{
    for(int i=0;i<v.size();i++)
    print(v[i],i==(int)(v.size())-1?suc:2);
}
typedef double db;
const db eps = 1e-6;
const db pi = acos(-1.0);
int sign(db k)
{
    if (k > eps)
        return 1;
    else if (k < -eps)
        return -1;
    return 0;
}
int cmp(db k1, db k2) { return sign(k1 - k2); }
struct point
{
    db x, y;
    point operator+(const point &k1) const { return (point){k1.x + x, k1.y + y}; }
    point operator-(const point &k1) const { return (point){x - k1.x, y - k1.y}; }
    point operator*(db k1) const { return (point){x * k1, y * k1}; }
    point operator/(db k1) const { return (point){x / k1, y / k1}; }
    int operator==(const point &k1) const { return cmp(x, k1.x) == 0 && cmp(y, k1.y) == 0; }
    db abs() { return sqrt(x * x + y * y); }
    db dis(point k1) { return ((*this) - k1).abs(); }
};
struct circle
{
    point o;
    db r;
    int inside(point k) { return cmp(r, o.dis(k)); }
};
circle getcircle(point k1, point k2, point k3)
{
    // 三点求圆
    db a1 = k2.x - k1.x, b1 = k2.y - k1.y, c1 = (a1 * a1 + b1 * b1) / 2;
    db a2 = k3.x - k1.x, b2 = k3.y - k1.y, c2 = (a2 * a2 + b2 * b2) / 2;
    db d = a1 * b2 - a2 * b1;
    point o = (point){k1.x + (c1 * b2 - c2 * b1) / d, k1.y + (a1 * c2 - a2 * c1) / d};
    return (circle){o, k1.dis(o)};
}
circle getScircle(vector<point> A)
{
    //随机增量法 最小圆覆盖
    random_shuffle(A.begin(), A.end());
    circle ans = (circle){A[0], 0};
    for (int i = 1; i < A.size(); i++)
        if (ans.inside(A[i]) == -1)
        {
            ans = (circle){A[i], 0};
            for (int j = 0; j < i; j++)
                if (ans.inside(A[j]) == -1)
                {
                    ans.o = (A[i] + A[j]) / 2;
                    ans.r = ans.o.dis(A[i]);
                    for (int k = 0; k < j; k++)
                        if (ans.inside(A[k]) == -1)
                            ans = getcircle(A[i], A[j], A[k]);
                }
        }
    return ans;
}
int main()
{
    int n;
    cin>>n;
    vector<point> a(n);
    for(int i=0;i<n;i++) cin>>a[i].x>>a[i].y;
    auto ans=getScircle(a);
    cout<<fixed<<setprecision(10)<<ans.r<<'\n';
}

Measured memory_bytes: 256