import java.util.Scanner;

public class Main {

    public static final int MOD = 1000000007;

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long a = Long.parseLong(sc.next());
        double b = Double.parseDouble(sc.next());
        long c = Math.round(b * 100);
        System.out.println(a * c / 100);
    }
} import java.util.Scanner; Scanner java.util public class Main {

    public static final int MOD = 1000000007;

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long a = Long.parseLong(sc.next());
        double b = Double.parseDouble(sc.next());
        long c = Math.round(b * 100);
        System.out.println(a * c / 100);
    }
} Main public static final int MOD = 1000000007; MOD 1000000007 public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long a = Long.parseLong(sc.next());
        double b = Double.parseDouble(sc.next());
        long c = Math.round(b * 100);
        System.out.println(a * c / 100);
    } main {
        Scanner sc = new Scanner(System.in);
        long a = Long.parseLong(sc.next());
        double b = Double.parseDouble(sc.next());
        long c = Math.round(b * 100);
        System.out.println(a * c / 100);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long a = Long.parseLong(sc.next()); a Long.parseLong(sc.next()) Long.parseLong Long sc.next() sc.next sc double b = Double.parseDouble(sc.next()); b Double.parseDouble(sc.next()) Double.parseDouble Double sc.next() sc.next sc long c = Math.round(b * 100); c Math.round(b * 100) Math.round Math b * 100 b 100 System.out.println(a * c / 100) System.out.println System.out System System.out a * c / 100 a * c a c 100 String[] args args public class Main {

    public static final int MOD = 1000000007;

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long a = Long.parseLong(sc.next());
        double b = Double.parseDouble(sc.next());
        long c = Math.round(b * 100);
        System.out.println(a * c / 100);
    }
} public class Main {

    public static final int MOD = 1000000007;

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long a = Long.parseLong(sc.next());
        double b = Double.parseDouble(sc.next());
        long c = Math.round(b * 100);
        System.out.println(a * c / 100);
    }
} Main
import java.util.Scanner;

public class Main {

    public static final int MOD = 1000000007;

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long a = Long.parseLong(sc.next());
        double b = Double.parseDouble(sc.next());
        long c = Math.round(b * 100);
        System.out.println(a * c / 100);
    }
}