import java.util.Scanner;

public class Main {

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

		long a = sc.nextLong();
		String s = sc.next();
		s = s.replace(".", "");
		long bx100 = Integer.parseInt(s);

		long tmp = a * bx100;
		long res = tmp / 100;

		System.out.printf("%d", res);
	}
} 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();
		String s = sc.next();
		s = s.replace(".", "");
		long bx100 = Integer.parseInt(s);

		long tmp = a * bx100;
		long res = tmp / 100;

		System.out.printf("%d", res);
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		long a = sc.nextLong();
		String s = sc.next();
		s = s.replace(".", "");
		long bx100 = Integer.parseInt(s);

		long tmp = a * bx100;
		long res = tmp / 100;

		System.out.printf("%d", res);
	} main {
		Scanner sc = new Scanner(System.in);

		long a = sc.nextLong();
		String s = sc.next();
		s = s.replace(".", "");
		long bx100 = Integer.parseInt(s);

		long tmp = a * bx100;
		long res = tmp / 100;

		System.out.printf("%d", res);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long a = sc.nextLong(); a sc.nextLong() sc.nextLong sc String s = sc.next(); s sc.next() sc.next sc s = s.replace(".", "") s s.replace(".", "") s.replace s "." "" long bx100 = Integer.parseInt(s); bx100 Integer.parseInt(s) Integer.parseInt Integer s long tmp = a * bx100; tmp a * bx100 a bx100 long res = tmp / 100; res tmp / 100 tmp 100 System.out.printf("%d", res) System.out.printf System.out System System.out "%d" res String[] args args public class Main {

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

		long a = sc.nextLong();
		String s = sc.next();
		s = s.replace(".", "");
		long bx100 = Integer.parseInt(s);

		long tmp = a * bx100;
		long res = tmp / 100;

		System.out.printf("%d", res);
	}
} public class Main {

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

		long a = sc.nextLong();
		String s = sc.next();
		s = s.replace(".", "");
		long bx100 = Integer.parseInt(s);

		long tmp = a * bx100;
		long res = tmp / 100;

		System.out.printf("%d", res);
	}
} Main
import java.util.Scanner;

public class Main {

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

		long a = sc.nextLong();
		String s = sc.next();
		s = s.replace(".", "");
		long bx100 = Integer.parseInt(s);

		long tmp = a * bx100;
		long res = tmp / 100;

		System.out.printf("%d", res);
	}
}