#include <bits/stdc++.h>
#define rep(i,j,k) for(int i=j;i<=k;i++)
using namespace std;
int read(){
    char ch=getchar();int x=0,f=1;
    for(;ch<'0'||ch>'9';ch=getchar())if(ch=='-')f=-1;
    for(;ch>='0'&&ch<='9';ch=getchar())x=x*10+ch-'0';
    return f*x;
}
int n;
const double eps=1e-7;
const int N=1000;
const double Pi=acos(-1);
int L[N+10];

double Angle(double r,double b){
    return acos((r*r+r*r-b*b)/2.0/r/r);
}
double chk(double mid){
    double sum=0;
    rep(i,1,n){
        sum+=Angle(mid,L[i]);
    }
    return sum;
}
int main(){
    n=read();
    rep(i,1,n){
        L[i]=read();
    }
    sort(L+1,L+n+1);

    double tmp=chk(L[n]/2.0+eps);
    double ll=eps;
    double rr=10000.0;
    if(tmp>2*Pi||fabs(tmp-2*Pi)<eps){
        while(fabs(rr-ll)>eps){
            double mid=(ll+rr)/2.0;
            if(chk(mid)<2*Pi){
                rr=mid;
            }else{
                ll=mid;
            }
        }
        printf("%.8f\n",(ll+rr)/2);
        return 0;
    }

    ll=L[n]/2.0+eps;
    n--;
    while(true){
        rr=ll*2;
        double sum1=chk(rr);
        double sum2=Angle(rr,L[n+1]);
        if(sum1<sum2){
            ll*=2;
        }else{
            break;
        }
    }
    
    while(fabs(rr-ll)>eps){
        double mid=(ll+rr)/2.0;
        if(chk(mid)<Angle(mid,L[n+1])){
            ll=mid;
        }else{
            rr=mid;
        }
    }
    printf("%.8f\n",(ll+rr)/2);
    return 0;
}