import java.util.Scanner;
public class Main
{
    public static void main(String[]args)
    {
        Scanner sc=new Scanner(System.in);
        int n=scan.nextInt();
       if(n<0)
        {
            System.out.println("Invalid input");
            return;
        }
        int[]arr=new int[n];
        int a=1;
        for(int i=0;i<n;i++)
        {
            if(!scan.hasNextInt())
            {
                System.out.println("Invalid input");
                return;
            }
            arr[i]=scan.nextInt();
            a*=arr[i];
        }
        System.out.println(a);
    }
}