#include<bits/stdc++.h>
using namespace std;
typedef pair<int,int> pii;

const int N=1005;
const double pi=acos(-1);

int n,a[N];
bool chk(double r){
    double sum=0;
    for(int i=1;i<=n;++i)sum+=asin(a[i]/r/2);
    return sum>pi;
}
int main(){
    ios::sync_with_stdio(0);cin.tie(0);
    cin>>n;
    for(int i=1;i<=n;++i)cin>>a[i];
    double l=*max_element(a+1,a+n+1)*.5,r=1e5;
    while(r-l>=1e-8){
        double mid=(l+r)/2;
        if(chk(mid))l=mid;
        else r=mid;
    }
    cout<<fixed<<setprecision(12)<<l<<'\n';
    //double area=0;
    //for(int i=1;i<=n;++i)area+=a[i]*sqrt(l*l-.25*a[i]*a[i]);
    //cout<<area<<'\n';
}