#include<iostream>
#include<cstdio>
#include<vector>
#include<queue>
#include<cmath>
#include<cstring>
#include<algorithm>
using namespace std;
typedef long long ll;
const int Max_n=110;

int n;
double a[Max_n];

int main()
{
    scanf("%d",&n);
    for(int i=0;i<n;i++)scanf("%lf",&a[i]);
    sort(a,a+n);
    double s=a[n-1];
    for(int i=n-2;i>=0;i--){
        s=2*sqrt(s*a[i]);
    }
    printf("%.3f\n",s);
    return 0;
}