import java.util.*;
import java.io.*;
import java.math.*;
public class Main{
    public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		PrintWriter ou = new PrintWriter(System.out);
		BigInteger n = BigInteger.ONE;
		Long a = Long.parseLong(sc.next());
		String bb = sc.next();
		long b = ((long)bb.charAt(0) - 48) * 1000 + 100 * ((long)bb.charAt(2) - 48) + ((long)bb.charAt(3) - 48) * 10;
		n = n.multiply(BigInteger.valueOf(a));
		n = n.multiply(BigInteger.valueOf(b));
		n = n.divide(BigInteger.valueOf((long)1000));
		ou.println(n);
		ou.flush();
	}
} import java.util.*; util.* java import java.io.*; io.* java import java.math.*; math.* java public class Main{
    public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		PrintWriter ou = new PrintWriter(System.out);
		BigInteger n = BigInteger.ONE;
		Long a = Long.parseLong(sc.next());
		String bb = sc.next();
		long b = ((long)bb.charAt(0) - 48) * 1000 + 100 * ((long)bb.charAt(2) - 48) + ((long)bb.charAt(3) - 48) * 10;
		n = n.multiply(BigInteger.valueOf(a));
		n = n.multiply(BigInteger.valueOf(b));
		n = n.divide(BigInteger.valueOf((long)1000));
		ou.println(n);
		ou.flush();
	}
} Main public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		PrintWriter ou = new PrintWriter(System.out);
		BigInteger n = BigInteger.ONE;
		Long a = Long.parseLong(sc.next());
		String bb = sc.next();
		long b = ((long)bb.charAt(0) - 48) * 1000 + 100 * ((long)bb.charAt(2) - 48) + ((long)bb.charAt(3) - 48) * 10;
		n = n.multiply(BigInteger.valueOf(a));
		n = n.multiply(BigInteger.valueOf(b));
		n = n.divide(BigInteger.valueOf((long)1000));
		ou.println(n);
		ou.flush();
	} main {
		Scanner sc = new Scanner(System.in);
		PrintWriter ou = new PrintWriter(System.out);
		BigInteger n = BigInteger.ONE;
		Long a = Long.parseLong(sc.next());
		String bb = sc.next();
		long b = ((long)bb.charAt(0) - 48) * 1000 + 100 * ((long)bb.charAt(2) - 48) + ((long)bb.charAt(3) - 48) * 10;
		n = n.multiply(BigInteger.valueOf(a));
		n = n.multiply(BigInteger.valueOf(b));
		n = n.divide(BigInteger.valueOf((long)1000));
		ou.println(n);
		ou.flush();
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) PrintWriter ou = new PrintWriter(System.out); ou new PrintWriter(System.out) BigInteger n = BigInteger.ONE; n BigInteger.ONE BigInteger BigInteger.ONE Long a = Long.parseLong(sc.next()); a Long.parseLong(sc.next()) Long.parseLong Long sc.next() sc.next sc String bb = sc.next(); bb sc.next() sc.next sc long b = ((long)bb.charAt(0) - 48) * 1000 + 100 * ((long)bb.charAt(2) - 48) + ((long)bb.charAt(3) - 48) * 10; b ((long)bb.charAt(0) - 48) * 1000 + 100 * ((long)bb.charAt(2) - 48) + ((long)bb.charAt(3) - 48) * 10 ((long)bb.charAt(0) - 48) * 1000 + 100 * ((long)bb.charAt(2) - 48) + ((long)bb.charAt(3) - 48) * 10 ((long)bb.charAt(0) - 48) * 1000 ((long)bb.charAt(0) - 48) (long)bb.charAt(0) bb.charAt bb 0 48 1000 100 * ((long)bb.charAt(2) - 48) 100 ((long)bb.charAt(2) - 48) (long)bb.charAt(2) bb.charAt bb 2 48 ((long)bb.charAt(3) - 48) * 10 ((long)bb.charAt(3) - 48) (long)bb.charAt(3) bb.charAt bb 3 48 10 n = n.multiply(BigInteger.valueOf(a)) n n.multiply(BigInteger.valueOf(a)) n.multiply n BigInteger.valueOf(a) BigInteger.valueOf BigInteger a n = n.multiply(BigInteger.valueOf(b)) n n.multiply(BigInteger.valueOf(b)) n.multiply n BigInteger.valueOf(b) BigInteger.valueOf BigInteger b n = n.divide(BigInteger.valueOf((long)1000)) n n.divide(BigInteger.valueOf((long)1000)) n.divide n BigInteger.valueOf((long)1000) BigInteger.valueOf BigInteger (long)1000 ou.println(n) ou.println ou n ou.flush() ou.flush ou String[] args args public class Main{
    public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		PrintWriter ou = new PrintWriter(System.out);
		BigInteger n = BigInteger.ONE;
		Long a = Long.parseLong(sc.next());
		String bb = sc.next();
		long b = ((long)bb.charAt(0) - 48) * 1000 + 100 * ((long)bb.charAt(2) - 48) + ((long)bb.charAt(3) - 48) * 10;
		n = n.multiply(BigInteger.valueOf(a));
		n = n.multiply(BigInteger.valueOf(b));
		n = n.divide(BigInteger.valueOf((long)1000));
		ou.println(n);
		ou.flush();
	}
} public class Main{
    public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		PrintWriter ou = new PrintWriter(System.out);
		BigInteger n = BigInteger.ONE;
		Long a = Long.parseLong(sc.next());
		String bb = sc.next();
		long b = ((long)bb.charAt(0) - 48) * 1000 + 100 * ((long)bb.charAt(2) - 48) + ((long)bb.charAt(3) - 48) * 10;
		n = n.multiply(BigInteger.valueOf(a));
		n = n.multiply(BigInteger.valueOf(b));
		n = n.divide(BigInteger.valueOf((long)1000));
		ou.println(n);
		ou.flush();
	}
} Main
import java.util.*;
import java.io.*;
import java.math.*;
public class Main{
    public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		PrintWriter ou = new PrintWriter(System.out);
		BigInteger n = BigInteger.ONE;
		Long a = Long.parseLong(sc.next());
		String bb = sc.next();
		long b = ((long)bb.charAt(0) - 48) * 1000 + 100 * ((long)bb.charAt(2) - 48) + ((long)bb.charAt(3) - 48) * 10;
		n = n.multiply(BigInteger.valueOf(a));
		n = n.multiply(BigInteger.valueOf(b));
		n = n.divide(BigInteger.valueOf((long)1000));
		ou.println(n);
		ou.flush();
	}
}