#include<bits/stdc++.h>
using namespace std;
#define nl '\n'
const int N = 1e5+5;

double a[N], b[N];

double dis(double x, double y, double xx, double yy){
    return sqrtl((x-xx)*(x-xx)+(y-yy)*(y-yy));
}

int main() {
    int n; cin >> n;
    double mxx = -2e9, mxy = -2e9;
    double mnx = 2e9, mny = 2e9;
    for(int i=0;i<n;++i) cin >> a[i] >> b[i];
    double d = -1.0;
    for(int i=0;i<n;++i){
        for(int j=0;j<n;++j){
            d = max(d, dis(a[i], b[i], a[j], b[j]));
            // cerr << d << endl;
        }
    }
    cout << fixed << setprecision(10) << d / 2 << nl;
}