import java.util.*;
import java.lang.*;
 
class Task4
{
	public static void main (String[] args)
	{
		Scanner input = new Scanner(System.in);
		int n = input.nextInt();
		double p=1;
		for(;n>0;n--) p*=input.nextDouble();
		System.out.println(Math.sqrt(Math.abs(p)));
	}
}