import java.io.*;
import java.util.*;
import java.lang.*;
import java.math.*;
public class Main 
{
    public static void main (String[] args) 
    {
    	
        Scanner cin=new Scanner(System.in);
        BigDecimal a = new BigDecimal(cin.next());
        BigDecimal b = new BigDecimal(cin.next());
        System.out.println(a.multiply(b));
	} 
}