import java.util.*;
import java.math.*;
public class Main{

    public static void main(String []args)
    {
        Scanner sc = new Scanner(System.in);
        String a = sc.next();
        double b = sc.nextDouble();
        BigDecimal c = new BigDecimal(a);
        BigDecimal d = BigDecimal.valueOf(b);
        System.out.println(c.multiply(d).toBigInteger());
    }
} import java.util.*; util.* java import java.math.*; math.* java public class Main{

    public static void main(String []args)
    {
        Scanner sc = new Scanner(System.in);
        String a = sc.next();
        double b = sc.nextDouble();
        BigDecimal c = new BigDecimal(a);
        BigDecimal d = BigDecimal.valueOf(b);
        System.out.println(c.multiply(d).toBigInteger());
    }
} Main public static void main(String []args)
    {
        Scanner sc = new Scanner(System.in);
        String a = sc.next();
        double b = sc.nextDouble();
        BigDecimal c = new BigDecimal(a);
        BigDecimal d = BigDecimal.valueOf(b);
        System.out.println(c.multiply(d).toBigInteger());
    } main {
        Scanner sc = new Scanner(System.in);
        String a = sc.next();
        double b = sc.nextDouble();
        BigDecimal c = new BigDecimal(a);
        BigDecimal d = BigDecimal.valueOf(b);
        System.out.println(c.multiply(d).toBigInteger());
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String a = sc.next(); a sc.next() sc.next sc double b = sc.nextDouble(); b sc.nextDouble() sc.nextDouble sc BigDecimal c = new BigDecimal(a); c new BigDecimal(a) BigDecimal d = BigDecimal.valueOf(b); d BigDecimal.valueOf(b) BigDecimal.valueOf BigDecimal b System.out.println(c.multiply(d).toBigInteger()) System.out.println System.out System System.out c.multiply(d).toBigInteger() c.multiply(d).toBigInteger c.multiply(d) c.multiply c d String []args args public class Main{

    public static void main(String []args)
    {
        Scanner sc = new Scanner(System.in);
        String a = sc.next();
        double b = sc.nextDouble();
        BigDecimal c = new BigDecimal(a);
        BigDecimal d = BigDecimal.valueOf(b);
        System.out.println(c.multiply(d).toBigInteger());
    }
} public class Main{

    public static void main(String []args)
    {
        Scanner sc = new Scanner(System.in);
        String a = sc.next();
        double b = sc.nextDouble();
        BigDecimal c = new BigDecimal(a);
        BigDecimal d = BigDecimal.valueOf(b);
        System.out.println(c.multiply(d).toBigInteger());
    }
} Main
import java.util.*;
import java.math.*;
public class Main{

    public static void main(String []args)
    {
        Scanner sc = new Scanner(System.in);
        String a = sc.next();
        double b = sc.nextDouble();
        BigDecimal c = new BigDecimal(a);
        BigDecimal d = BigDecimal.valueOf(b);
        System.out.println(c.multiply(d).toBigInteger());
    }
}