#include <bits/stdc++.h>
#include <unistd.h>
 
using namespace std;
 
typedef long long ll;
typedef pair<ll,ll> P;
 
long long int INF = 3e18;
const ll fact_table = 800008;
double Pi = 3.1415926535897932384626;
 
//vector<ll> G[550010];
vector<P> tree[500010];
priority_queue <ll> pql;
priority_queue <P> pqp;
//big priority queue
priority_queue <ll,vector<ll>,greater<ll> > pqls;
priority_queue <P,vector<P>,greater<P> > pqps;
//small priority queue
//top pop
 
ll dx[8]={1,0,-1,0,1,1,-1,-1};
ll dy[8]={0,1,0,-1,1,-1,-1,1};
char dir[] = "DRUL";
//ll bit[500005];
//↓,→,↑,←
 
 
#define p(x) cout<<x<<"\n";
#define el cout<<endl;
#define pe(x) cout<<(x)<<" ";
#define ps(x) cout<<fixed<<setprecision(25)<<x<<endl;
#define pu(x) cout<<(x);
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define CLEAR(a) a = decltype(a)(); 
 
 
//ll mod = 998244353;
ll mod = 1000000007;
 
ll rui(ll number1,ll number2){
 
    if(number2 == 0){
        return 1;
    }else{
        ll number3 = rui(number1,number2 / 2);
        number3 *= number3;
        number3 %= mod;
        if(number2%2==1){
            number3 *= number1;
            number3 %= mod;
        }
        return number3;
    }
}
ll gcd(ll number1,ll number2){
 
    if(number1 > number2){
        swap(number1,number2);
    }
    if(number1 == 0 || number1 == number2){
        return number2;
    }else{
        return gcd(number2 % number1,number1);
    }
}
void YES(bool condition){
 
    if(condition){
        p("YES");
    }else{
        p("NO");
    }
    return;
}
void Yes(bool condition){
 
    if(condition){
        p("Yes");
    }else{
        p("No");
    }
    return;
}
 
/*
ll fact[fact_table + 5],rfact[fact_table + 5];
 
void c3_init(){
    fact[0] = rfact[0] = 1;
    for(ll i=1; i<=fact_table; i++){
        fact[i] = (fact[i-1]*i) % mod;
    }
    rfact[fact_table] = rui(fact[fact_table],mod - 2);
    for(ll i=fact_table; i>=1; i--){
       rfact[i-1] = rfact[i] * i;
       rfact[i-1] %= mod;
    }
    return;}
ll c3(ll n,ll r){
    return (((fact[n] * rfact[r]) % mod ) * rfact[n-r]) % mod;}
*/
 
ll n,m,num,sum,a,b,c,d,e,g,h,w,i,j,q,r,l;
ll k;
ll ans;
ll x[500005], y[500005], z[200005];
char s[500005], t[500005];
string table[100];
bool used[500005];

double distance(double xd, double yd){
    double maxi = 0.0;
    for(ll i=0;i<n;i++){
        double now = (xd - x[i]) * (xd - x[i]) + (yd - y[i]) * (yd - y[i]);
        now = sqrt(now);
        maxi = max(maxi, now);
    }
    return maxi;
}
int main(){
    
    
    cin.tie(0);
    ios::sync_with_stdio(false);

    cin >> n;
    ll sum1 = 0, sum2 = 0;
    for(ll i=0;i<n;i++){
        cin >> x[i] >> y[i];
        sum1 += x[i];
        sum2 += y[i];
    }
    double x, y;
    x = (double)(sum1) / (double)n;
    y = (double)sum2 / (double)n;
    double move = 100.0;
    for(ll i=0;i<50000;i++){
        double newx, newy;
        bool update = false;
        for(ll j=0;j<20;j++){
            double theta = 2.0 * Pi * ((double)j) / 20.0;
            //ps(cos(theta));
            theta += (double)rand();
            double nx = x + move * cos(theta);
            double ny = y + move * sin(theta);
            if(distance(x, y) > distance(nx, ny)){
                update = true;
                newx = nx;
                newy = ny;
            }
        }
        if(update){
            x = newx;
            y = newy;
        }
      move *= 0.999;
        /*
        ps(x);ps(y);
        ps(move);
        p("-------------");
        */
    }
    double ans = distance(x, y);
    ps(ans);

    return 0;
}









Measured memory_bytes: 17152