// editor3
import java.util.*;
public class duplicate
{
    public static void main(String[] args)
    {
        Scanner sc =new Scanner(System.in);
        int n=sc.nextInt();
        int[] arr=new int[n];
        long l=1;
        boolean valid=false;
        for(int i=0;i<n;i++)
        {
            
            if(!sc.hasNextInt())
            {
                valid=true;
                
                     break;           
            }
            arr[i]=sc.nextInt();
        if(arr[i]<-10000 || arr[i>10000])
        {
            valid=true;
                
                     break;  
        }
        
             l=l*arr[i];
        }
        if(valid){
            System.out.println("Invalid input");
        }else{
        
        System.out.println(l);
        }
    }
    
}