Untitled

    #include <bits/stdc++.h>
    #define endl '\n'
    #define maxn 105
    #define TASK bai1
    #define For(i,a,b) for ( int i = a; i <= b; i++ )
    #define MOD 100000000000007

    using namespace std;
    int x[maxn],n,y[maxn];
    double p,s,ans = -MOD,a,b,c,r;
    void inp()
    {
        cin >> n;
        For(i,1,n)
            cin >> x[i] >> y[i];
    }

    bool check(double a, double b, double c)
    {
        if (a*a >= b*b + c*c) return true;
        if (a*a < b*b + c*c) return false;

    }
    void swa(int a, int b, int c)
    {
        if (b < c) swap(b,c);
        if (a < b) swap(a,b);
        if (a < c) swap(a,c);
    }
    double Tinh(int i, int j)
    {
        double res = sqrt((x[i] - x[j])*(x[i] - x[j]) + (y[i] - y[j])*(y[i] - y[j]));
        return res;
    }
    double Rad(double a, double b, double c)
    {
         p = (a + b + c)/2;
         s =sqrt(p*(p-a)*(p-b)*(p-c));
         double res = (a*b*c)/(4*s);
         return res;
    }
    void solve()
    {
        For(i,1,n-2)
        For(j,i+1,n-1)
        For(k,j+1,n)
        {
            a = Tinh(i,j); b = Tinh(j,k); c = Tinh(i,k);
            swa(a,b,c);
            if(check(a,b,c)) r = a/2;
            else r = Rad(a,b,c);
            ans = max(ans,r);
        }
        cout << setprecision(3) << fixed << ans;
    }
    int main()
    {
    ios_base:: sync_with_stdio(0);
    cin.tie(0);
    if(fopen("bai1.inp","r")){
        freopen("bai1.inp","r",stdin);
    }
    inp();
    solve();
    }