import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long A = sc.nextLong();
        double B = sc.nextDouble();
        sc.close();

        long hyakubaiB = (long) (Math.round(B * 100));

        System.out.println((A * hyakubaiB) / 100);
    }
} import java.util.Scanner; Scanner java.util public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long A = sc.nextLong();
        double B = sc.nextDouble();
        sc.close();

        long hyakubaiB = (long) (Math.round(B * 100));

        System.out.println((A * hyakubaiB) / 100);
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long A = sc.nextLong();
        double B = sc.nextDouble();
        sc.close();

        long hyakubaiB = (long) (Math.round(B * 100));

        System.out.println((A * hyakubaiB) / 100);
    } main {
        Scanner sc = new Scanner(System.in);
        long A = sc.nextLong();
        double B = sc.nextDouble();
        sc.close();

        long hyakubaiB = (long) (Math.round(B * 100));

        System.out.println((A * hyakubaiB) / 100);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long A = sc.nextLong(); A sc.nextLong() sc.nextLong sc double B = sc.nextDouble(); B sc.nextDouble() sc.nextDouble sc sc.close() sc.close sc long hyakubaiB = (long) (Math.round(B * 100)); hyakubaiB (long) (Math.round(B * 100)) Math.round Math B * 100 B 100 System.out.println((A * hyakubaiB) / 100) System.out.println System.out System System.out (A * hyakubaiB) / 100 (A * hyakubaiB) A hyakubaiB 100 String[] args args public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long A = sc.nextLong();
        double B = sc.nextDouble();
        sc.close();

        long hyakubaiB = (long) (Math.round(B * 100));

        System.out.println((A * hyakubaiB) / 100);
    }
} public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long A = sc.nextLong();
        double B = sc.nextDouble();
        sc.close();

        long hyakubaiB = (long) (Math.round(B * 100));

        System.out.println((A * hyakubaiB) / 100);
    }
} Main
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long A = sc.nextLong();
        double B = sc.nextDouble();
        sc.close();

        long hyakubaiB = (long) (Math.round(B * 100));

        System.out.println((A * hyakubaiB) / 100);
    }
}
