/*{{{*/
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<string>
#include<iostream>
#include<sstream>
#include<set>
#include<map>
#include<queue>
#include<bitset>
#include<vector>
#include<limits.h>
#include<assert.h>
#define SZ(X) ((int)(X).size())
#define ALL(X) (X).begin(), (X).end()
#define REP(I, N) for (int I = 0; I < (N); ++I)
#define REPP(I, A, B) for (int I = (A); I < (B); ++I)
#define FOR(I, A, B) for (int I = (A); I <= (B); ++I)
#define FORS(I, S) for (int I = 0; S[I]; ++I)
#define RS(X) scanf("%s", (X))
#define SORT_UNIQUE(c) (sort(c.begin(),c.end()), c.resize(distance(c.begin(),unique(c.begin(),c.end()))))
#define GET_POS(c,x) (lower_bound(c.begin(),c.end(),x)-c.begin())
#define CASET int ___T; scanf("%d", &___T); for(int cs=1;cs<=___T;cs++)
#define MP make_pair
#define PB push_back
#define MS0(X) memset((X), 0, sizeof((X)))
#define MS1(X) memset((X), -1, sizeof((X)))
#define LEN(X) strlen(X)
#define F first
#define S second
using namespace std;
typedef long long LL;
typedef unsigned long long ULL;
typedef long double LD;
typedef pair<int,int> PII;
typedef vector<int> VI;
typedef vector<LL> VL;
typedef vector<PII> VPII;
typedef pair<LL,LL> PLL;
typedef vector<PLL> VPLL;
template<class T> void _R(T &x) { cin >> x; }
void _R(int &x) { scanf("%d", &x); }
void _R(LL &x) { scanf("%lld", &x); }
void _R(double &x) { scanf("%lf", &x); }
void _R(char &x) { scanf(" %c", &x); }
void _R(char *x) { scanf("%s", x); }
void R() {}
template<class T, class... U> void R(T &head, U &... tail) { _R(head); R(tail...); }
template<class T> void _W(const T &x) { cout << x; }
void _W(const int &x) { printf("%d", x); }
void _W(const LL &x) { printf("%lld", x); }
void _W(const double &x) { printf("%.16f", x); }
void _W(const char &x) { putchar(x); }
void _W(const char *x) { printf("%s", x); }
template<class T,class U> void _W(const pair<T,U> &x) {_W(x.F); putchar(' '); _W(x.S);}
template<class T> void _W(const vector<T> &x) { for (auto i = x.begin(); i != x.end(); _W(*i++)) if (i != x.cbegin()) putchar(' '); }
void W() {}
template<class T, class... U> void W(const T &head, const U &... tail) { _W(head); putchar(sizeof...(tail) ? ' ' : '\n'); W(tail...); }
#ifdef HOME
 #define DEBUG(...) {printf("# ");printf(__VA_ARGS__);puts("");}
#else
 #define DEBUG(...)
#endif
int MOD = 1e9+7;
double eps=1e-12;
void ADD(LL& x,LL v){x=(x+v)%MOD;if(x<0)x+=MOD;}
/*}}}*/
const int size = 1e6+10;
struct P { double x,y; } p[size],q[3];
double dis2( P a, P b ) { return (a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y); }
P operator -( P a, P b ) { return (P){a.x-b.x,a.y-b.y}; }
P operator +( P a, P b ) { return (P){a.x+b.x,a.y+b.y}; }
P operator /( P a, double b ) { return (P){a.x/b,a.y/b}; }
double abs2( P a ) { return a.x*a.x+a.y*a.y; }
double dot( P a, P b ) { return a.x*b.x+a.y*b.y; }
double X( P a, P b ) { return a.x*b.y-a.y*b.x; }
double X( P a, P b, P c ) { return X(b-a,c-a); }
struct C {
    P o; double r2;
    C() { o.x=o.y=r2=0; }
    C( P a ) { o=a; r2=0; }
    C( P a, P b ) { o=(a+b)/2; r2=dis2(o,a); }
    C( P a, P b, P c ) {
        double i,j,k,A=2*X(a,b,c)*X(a,b,c);
        i=abs2(b-c)*dot(a-b,a-c);
        j=abs2(a-c)*dot(b-a,b-c);
        k=abs2(a-b)*dot(c-a,c-b);
        o.x=(i*a.x+j*b.x+k*c.x)/A;
        o.y=(i*a.y+j*b.y+k*c.y)/A;
        r2=dis2(o,a);
    }
    bool cover( P a ) { return dis2(o,a)<=r2+eps; }
};
C MEC( int n, int m ) {
    C mec;
    if ( m==1 ) mec=C(q[0]);
    else if ( m==2 ) mec=C(q[0],q[1]);
    else if ( m==3 ) return C(q[0],q[1],q[2]);
    for ( int i=0; i<n; i++ )
        if ( !mec.cover(p[i]) ) {
            q[m]=p[i];
            mec=MEC(i,m+1);
        }
    return mec;
}
int main() {
    srand(514);
    int n,i; C mec;
    while( ~scanf("%d",&n)&&n ) {
        for ( i=0; i<n; i++ ) scanf("%lf%lf",&p[i].x,&p[i].y);
        random_shuffle(p,p+n);
        mec=MEC(n,0);
        printf("%.12f\n",sqrt(mec.r2));
    }
    return 0;
}


Measured memory_bytes: 256