import java.util.*;

public class Main{
    public static void main(String[] args)
    {
       

        Scanner sc=new Scanner(System.in);
        int a=sc.nextInt();
        double b=sc.nextDouble();
      long ans=(long)(a*(b*100))/100;
      System.out.println(ans);

    }
} import java.util.*; util.* java public class Main{
    public static void main(String[] args)
    {
       

        Scanner sc=new Scanner(System.in);
        int a=sc.nextInt();
        double b=sc.nextDouble();
      long ans=(long)(a*(b*100))/100;
      System.out.println(ans);

    }
} Main public static void main(String[] args)
    {
       

        Scanner sc=new Scanner(System.in);
        int a=sc.nextInt();
        double b=sc.nextDouble();
      long ans=(long)(a*(b*100))/100;
      System.out.println(ans);

    } main {
       

        Scanner sc=new Scanner(System.in);
        int a=sc.nextInt();
        double b=sc.nextDouble();
      long ans=(long)(a*(b*100))/100;
      System.out.println(ans);

    } Scanner sc=new Scanner(System.in); sc new Scanner(System.in) int a=sc.nextInt(); a sc.nextInt() sc.nextInt sc double b=sc.nextDouble(); b sc.nextDouble() sc.nextDouble sc long ans=(long)(a*(b*100))/100; ans (long)(a*(b*100))/100 (long)(a*(b*100)) a (b*100) b 100 100 System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main{
    public static void main(String[] args)
    {
       

        Scanner sc=new Scanner(System.in);
        int a=sc.nextInt();
        double b=sc.nextDouble();
      long ans=(long)(a*(b*100))/100;
      System.out.println(ans);

    }
} public class Main{
    public static void main(String[] args)
    {
       

        Scanner sc=new Scanner(System.in);
        int a=sc.nextInt();
        double b=sc.nextDouble();
      long ans=(long)(a*(b*100))/100;
      System.out.println(ans);

    }
} Main
import java.util.*;

public class Main{
    public static void main(String[] args)
    {
       

        Scanner sc=new Scanner(System.in);
        int a=sc.nextInt();
        double b=sc.nextDouble();
      long ans=(long)(a*(b*100))/100;
      System.out.println(ans);

    }
}
