import java.math.BigDecimal;
import java.util.Scanner;

public class Main {

  public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);

    BigDecimal a = new BigDecimal(sc.next());
    BigDecimal b = new BigDecimal(sc.next());
    b = b.multiply(a);
    long p = b.longValue();

    System.out.println(p);
  }
} import java.math.BigDecimal; BigDecimal java.math import java.util.Scanner; Scanner java.util public class Main {

  public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);

    BigDecimal a = new BigDecimal(sc.next());
    BigDecimal b = new BigDecimal(sc.next());
    b = b.multiply(a);
    long p = b.longValue();

    System.out.println(p);
  }
} Main public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);

    BigDecimal a = new BigDecimal(sc.next());
    BigDecimal b = new BigDecimal(sc.next());
    b = b.multiply(a);
    long p = b.longValue();

    System.out.println(p);
  } main {

    Scanner sc = new Scanner(System.in);

    BigDecimal a = new BigDecimal(sc.next());
    BigDecimal b = new BigDecimal(sc.next());
    b = b.multiply(a);
    long p = b.longValue();

    System.out.println(p);
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) BigDecimal a = new BigDecimal(sc.next()); a new BigDecimal(sc.next()) BigDecimal b = new BigDecimal(sc.next()); b new BigDecimal(sc.next()) b = b.multiply(a) b b.multiply(a) b.multiply b a long p = b.longValue(); p b.longValue() b.longValue b System.out.println(p) System.out.println System.out System System.out p String[] args args public class Main {

  public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);

    BigDecimal a = new BigDecimal(sc.next());
    BigDecimal b = new BigDecimal(sc.next());
    b = b.multiply(a);
    long p = b.longValue();

    System.out.println(p);
  }
} public class Main {

  public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);

    BigDecimal a = new BigDecimal(sc.next());
    BigDecimal b = new BigDecimal(sc.next());
    b = b.multiply(a);
    long p = b.longValue();

    System.out.println(p);
  }
} Main
import java.math.BigDecimal;
import java.util.Scanner;

public class Main {

  public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);

    BigDecimal a = new BigDecimal(sc.next());
    BigDecimal b = new BigDecimal(sc.next());
    b = b.multiply(a);
    long p = b.longValue();

    System.out.println(p);
  }
}