#include <bits/stdc++.h>
#define ll long long
using namespace std;
const ll N = 1e6, mod = 1e9 + 7, inf = 1e18;
double eps = 0.0000000001;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int n;
cin >> n;
vector<long double> x(n);
vector<long double> y(n);
for (int i = 0; i < n; i++) {
cin >> x[i] >> y[i];
}
long double l = 0;
long double r = 1e15;
map<pair<int, int>, int> vis;
auto dfs = [&] (long double x1, long double y1, auto &dfs, long double r) -> void {
vis[{x1, y1}] = 1;
for (int i = 0; i < n; i++) {
long double d = abs(x1 - x[i]) * abs(x1 - x[i]) + abs(y1 - y[i]) * abs(y1 - y[i]);
long double e = r * r * 4;
if (vis[{x[i], y[i]}] == 0 && d <= e) {
dfs(x[i], y[i], dfs, r);
}
}
};
long double best = 0;
while (r - l >= eps) {
long double m = (l + r) / 2;
vis.clear();
dfs(x[0], y[0], dfs, m);
bool ok = true;
for (int i = 0; i < n; i++) {
if (vis[{x[i], y[i]}] == 0) {
ok = false;
}
}
if (ok) {
r = m;
best = r;
}
else {
l = m;
}
}
cout << setprecision(7) << fixed << best << '\n';
}
