import java.util.Scanner;

public class Main {
    public static void main(String args[]) {
        Scanner scan = new Scanner(System.in);

        long a = scan.nextLong();
        String b = scan.next();

        long sum = a * Integer.parseInt(b.replace(".", ""));
        System.out.println(sum / 100);
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String args[]) {
        Scanner scan = new Scanner(System.in);

        long a = scan.nextLong();
        String b = scan.next();

        long sum = a * Integer.parseInt(b.replace(".", ""));
        System.out.println(sum / 100);
    }
} Main public static void main(String args[]) {
        Scanner scan = new Scanner(System.in);

        long a = scan.nextLong();
        String b = scan.next();

        long sum = a * Integer.parseInt(b.replace(".", ""));
        System.out.println(sum / 100);
    } main {
        Scanner scan = new Scanner(System.in);

        long a = scan.nextLong();
        String b = scan.next();

        long sum = a * Integer.parseInt(b.replace(".", ""));
        System.out.println(sum / 100);
    } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) long a = scan.nextLong(); a scan.nextLong() scan.nextLong scan String b = scan.next(); b scan.next() scan.next scan long sum = a * Integer.parseInt(b.replace(".", "")); sum a * Integer.parseInt(b.replace(".", "")) a Integer.parseInt(b.replace(".", "")) Integer.parseInt Integer b.replace(".", "") b.replace b "." "" System.out.println(sum / 100) System.out.println System.out System System.out sum / 100 sum 100 String args[] args public class Main {
    public static void main(String args[]) {
        Scanner scan = new Scanner(System.in);

        long a = scan.nextLong();
        String b = scan.next();

        long sum = a * Integer.parseInt(b.replace(".", ""));
        System.out.println(sum / 100);
    }
} public class Main {
    public static void main(String args[]) {
        Scanner scan = new Scanner(System.in);

        long a = scan.nextLong();
        String b = scan.next();

        long sum = a * Integer.parseInt(b.replace(".", ""));
        System.out.println(sum / 100);
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String args[]) {
        Scanner scan = new Scanner(System.in);

        long a = scan.nextLong();
        String b = scan.next();

        long sum = a * Integer.parseInt(b.replace(".", ""));
        System.out.println(sum / 100);
    }
}
