#include <bits/stdc++.h>
#include <stdio.h>
#include <iostream>
#include <cstdio>
#include <bitset>
#include <algorithm>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <string>
#include <string.h>
#include <cmath>
#include <utility>
#include <functional>
#include <map>
#include <set>
#include <cctype>
#include <fstream>
#include <numeric>
#include <iomanip>
#include <cstring>
using namespace std;
using ll = long long;
#define ALL(a) (a).begin(), (a).end()

#define FOR(i, a, b) for (long long int i = (a); i <= (b); i++)
#define RFOR(i, a, b) for (long long int i = (a); i >= (b); i--)
#define MOD 1000000007
#define LLONG_MAXs 9223372036854775800 / 2

#define ALL(a) (a).begin(), (a).end()

#include <iostream>
#include <cmath>
using namespace std;

bool isPrimeNum(ll x)
{ // 素数である場合 true を返す
	if (x <= 1)
	{ // 1以下である場合は素数でないことがすぐにわかる
		return false;
	}
	// sqrt( double型 ) は引数の平方根を double型で返すので、int型でキャスト
	int n = (int)sqrt((double)x);
	for (int i = 2; i <= n; i++)
	{
		if (x % i == 0)
		{ // 割り切る整数がある場合、即判定終了
			return false;
		}
	}
	return true; // 割り切る整数がない場合、素数である
}

ll myPow(ll x, ll n, ll m)
{
	if (n == 0)
		return 1;
	if (n % 2 == 0)
		return myPow(x * x % m, n / 2, m);
	else
		return x * myPow(x, n - 1, m) % m;
}

constexpr ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
constexpr ll lcm(ll a, ll b) { return a * b / gcd(a, b); }
constexpr ll abs(ll a, ll b)
{
	if (a >= b)
		return a - b;
	if (a < b)
		return b - a;
}
constexpr double dabs(double a, double b)
{
	if (a >= b)
		return a - b;
	if (a < b)
		return b - a;
}
constexpr ll min(ll a, ll b)
{
	if (a >= b)
		return b;
	if (a < b)
		return a;
}

constexpr ll max(ll a, ll b)
{
	if (a >= b)
		return a;
	if (a < b)
		return b;
}

int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};

int dx8[8] = {1, 0, -1, 0, 1, -1, 1, -1};
int dy8[8] = {0, 1, 0, -1, 1, 1, -1, -1};

class UnionFind
{
public:
	//親の番号を格納する。親だった場合は-(その集合のサイズ)
	vector<int> Parent;

	//作るときはParentの値を全て-1にする
	//こうすると全てバラバラになる
	UnionFind(int N)
	{
		Parent = vector<int>(N, -1);
	}

	//Aがどのグループに属しているか調べる
	int root(int A)
	{
		if (Parent[A] < 0)
			return A;
		return Parent[A] = root(Parent[A]);
	}

	//自分のいるグループの頂点数を調べる
	int size(int A)
	{
		return -Parent[root(A)]; //親をとってきたい]
	}
	bool issame(int x, int y)
	{
		return root(x) == root(y);
	}
	//AとBをくっ付ける
	bool connect(int A, int B)
	{
		//AとBを直接つなぐのではなく、root(A)にroot(B)をくっつける
		A = root(A);
		B = root(B);
		if (A == B)
		{
			//すでにくっついてるからくっ付けない
			return false;
		}

		//大きい方(A)に小さいほう(B)をくっ付けたい
		//大小が逆だったらひっくり返しちゃう。
		if (size(A) < size(B))
			swap(A, B);

		//Aのサイズを更新する
		Parent[A] += Parent[B];
		//Bの親をAに変更する
		Parent[B] = A;

		return true;
	}
};

long long fac[510000], finv[510000], inv[510000];

// テーブルを作る前処理
void COMinit()
{
	fac[0] = fac[1] = 1;
	finv[0] = finv[1] = 1;
	inv[1] = 1;
	for (int i = 2; i < 510000; i++)
	{
		fac[i] = fac[i - 1] * i % MOD;
		inv[i] = MOD - inv[MOD % i] * (MOD / i) % MOD;
		finv[i] = finv[i - 1] * inv[i] % MOD;
	}
}

// 二項係数計算
long long COM(int n, int k)
{
	if (n < k)
		return 0;
	if (n < 0 || k < 0)
		return 0;
	return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}

long long modinv(long long a, long long m)
{
	long long b = m, u = 1, v = 0;
	while (b)
	{
		long long t = a / b;
		a -= t * b;
		swap(a, b);
		u -= t * v;
		swap(u, v);
	}
	u %= m;
	if (u < 0)
		u += m;
	return u;
}
string replaceAll(string &replacedStr, string from, string to)
{
	unsigned int pos = replacedStr.find(from);
	int toLen = to.length();

	if (from.empty())
	{
		return replacedStr;
	}

	while ((pos = replacedStr.find(from, pos)) != std::string::npos)
	{
		replacedStr.replace(pos, from.length(), to);
		pos += toLen;
	}
	return replacedStr;
}

void yn(bool flag)
{
	if (flag)
	{
		cout << "Yes" << endl;
	}
	else
	{
		cout << "No" << endl;
	}
	return;
}
void YN(bool flag)
{
	if (flag)
	{
		cout << "YES" << endl;
	}
	else
	{
		cout << "NO" << endl;
	}
	return;
}

std::vector<ll> enum_div(ll n) //nの約数を列挙
{
	std::vector<ll> ret;
	for (ll i = 1; i * i <= n; ++i)
	{
		if (n % i == 0)
		{
			ret.push_back(i);
			if (i != 1 && i * i != n)
			{
				ret.push_back(n / i);
			}
		}
	}
	ret.push_back(n);
	return ret;
}

void Ssort(int no, char *month[])
{
	int i, j;
	char *temp;
	for (i = 0; i < no; i++)
	{
		for (j = i + 1; j < no; j++)
		{
			if (strcmp((month[i]), (month[j])) > 0)
			{
				temp = *(month + i);
				*(month + i) = *(month + j);
				*(month + j) = temp;
			}
		}
	}
}

// グラフセット
struct Edge
{
	ll to;	 // 辺の行き先
	ll weight; // 辺の重み
	Edge(int t, int w) : to(t), weight(w) {}
};
//using Graph = vector<vector<Edge>>;
using Graph = vector<vector<ll>>;

//cout<<std::setprecision(30)
int main()
{
	ll N, K;
	cin >> N;
	double x[N], y[N];
	FOR(i, 0, N - 1)
	{
		cin >> x[i] >> y[i];
	}

	double ans = 999999999999;
	double eps = 0.0000001;
	FOR(i, 0, N - 1)
	{
		FOR(j, i + 1, N - 1)
		{
			FOR(k, j + 1, N - 1)
			{
				//cerr << i << j << k << endl;
				double x1, x2, x3, y1, y2, y3, G, Xc, Yc, Xd, Yd, Xe, Ye;
				x1 = x[i];
				y1 = y[i];

				x2 = x[j];
				y2 = y[j];

				x3 = x[k];
				y3 = y[k];

				G = (y2 * x1 - y1 * x2 + y3 * x2 - y2 * x3 + y1 * x3 - y3 * x1);
				Xc = ((x1 * x1 + y1 * y1) * (y2 - y3) + (x2 * x2 + y2 * y2) * (y3 - y1) + (x3 * x3 + y3 * y3) * (y1 - y2)) / (2 * G);
				Yc = -((x1 * x1 + y1 * y1) * (x2 - x3) + (x2 * x2 + y2 * y2) * (x3 - x1) + (x3 * x3 + y3 * y3) * (x1 - x2)) / (2 * G);

				Xd = (((x1 * x1 + y1 * y1) - (x2 * x2 + y2 * y2)) * (y2 - y3) - ((x2 * x2 + y2 * y2) - (x3 * x3 + y3 * y3)) * (y1 - y2)) / (2 * ((x1 - x2) * (y2 - y3) - (x2 - x3) * (y1 - y2)));
				Yd = (((y1 * y1 + x1 * x1) - (y2 * y2 + x2 * x2)) * (x2 - x3) - ((y2 * y2 + x2 * x2) - (y3 * y3 + x3 * x3)) * (x1 - x2)) / (2 * ((y1 - y2) * (x2 - x3) - (y2 - y3) * (x1 - x2)));

				G = (1 + eps) * sqrt((x1 - Xc) * (x1 - Xc) + (y1 - Yc) * (y1 - Yc));
				cout << std::setprecision(30);
				//std::cout << Xc << " " << Yc << " " << G << std::endl;
				ll f = 0;
				FOR(ii, 0, N - 1)
				{
					double dis;
					dis = sqrt((x[ii] - Xc) * (x[ii] - Xc) + (y[ii] - Yc) * (y[ii] - Yc));
					if (dis > G)
						f++;
				}
				if (f == 0)
				{
					ans = min(ans, G);
				}
				//cout << f << endl;
			}
		}
	}

	FOR(i, 0, N - 1)
	{
		FOR(j, i + 1, N - 1)
		{

			//cerr << i << j << k << endl;
			double x1, x2, x3, y1, y2, y3, G, Xc, Yc, Xd, Yd, Xe, Ye;
			x1 = x[i];
			y1 = y[i];

			x2 = x[j];
			y2 = y[j];

			Xc = (x[i]+x[j])/2;
			Yc = (y[i]+y[j])/2;

			G = (1 + eps) * sqrt((x[i] - x[j]) * (x[i] - x[j]) + (y[i] - y[j]) * (y[i] - y[j])) / 2;;
			cout << std::setprecision(30);
			//std::cout << Xc << " " << Yc << " " << G << std::endl;
			ll f = 0;
			FOR(ii, 0, N - 1)
			{
				double dis;
				dis = sqrt((x[ii] - Xc) * (x[ii] - Xc) + (y[ii] - Yc) * (y[ii] - Yc));
				if (dis > G)
					f++;
			}
			if (f == 0)
			{
				ans = min(ans, G);
			}
			//cout << f << endl;
		}
	}

	cout << std::setprecision(30);
	if (N == 2)
	{
		ans = sqrt((x[0] - x[1]) * (x[0] - x[1]) + (y[0] - y[1]) * (y[0] - y[1])) / 2;
	}

	cout << ans << endl;

	return 0;
}

Measured memory_bytes: 256