
import java.util.Scanner;

public class Main {

  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    long a = sc.nextLong();
    long b = Long.parseLong(sc.next().replace(".",""));
    sc.close();

    long x = a * b / 100;

    System.out.println(x);
  }

} 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();
    long b = Long.parseLong(sc.next().replace(".",""));
    sc.close();

    long x = a * b / 100;

    System.out.println(x);
  }

} Main public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    long a = sc.nextLong();
    long b = Long.parseLong(sc.next().replace(".",""));
    sc.close();

    long x = a * b / 100;

    System.out.println(x);
  } main {
    Scanner sc = new Scanner(System.in);
    long a = sc.nextLong();
    long b = Long.parseLong(sc.next().replace(".",""));
    sc.close();

    long x = a * b / 100;

    System.out.println(x);
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long a = sc.nextLong(); a sc.nextLong() sc.nextLong sc long b = Long.parseLong(sc.next().replace(".","")); b Long.parseLong(sc.next().replace(".","")) Long.parseLong Long sc.next().replace(".","") sc.next().replace sc.next() sc.next sc "." "" sc.close() sc.close sc long x = a * b / 100; x a * b / 100 a * b a b 100 System.out.println(x) System.out.println System.out System System.out x String[] args args public class Main {

  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    long a = sc.nextLong();
    long b = Long.parseLong(sc.next().replace(".",""));
    sc.close();

    long x = a * b / 100;

    System.out.println(x);
  }

} public class Main {

  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    long a = sc.nextLong();
    long b = Long.parseLong(sc.next().replace(".",""));
    sc.close();

    long x = a * b / 100;

    System.out.println(x);
  }

} Main

import java.util.Scanner;

public class Main {

  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    long a = sc.nextLong();
    long b = Long.parseLong(sc.next().replace(".",""));
    sc.close();

    long x = a * b / 100;

    System.out.println(x);
  }

}
