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

public class Main {
  public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);
    long a = sc.nextLong();
    float b = sc.nextFloat();

    int b2 = Math.round(b * 100);

    long total = a * b2 / 100;

    String result = BigDecimal.valueOf(total).toPlainString();

    System.out.println(result);

  }
} 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);
    long a = sc.nextLong();
    float b = sc.nextFloat();

    int b2 = Math.round(b * 100);

    long total = a * b2 / 100;

    String result = BigDecimal.valueOf(total).toPlainString();

    System.out.println(result);

  }
} Main public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);
    long a = sc.nextLong();
    float b = sc.nextFloat();

    int b2 = Math.round(b * 100);

    long total = a * b2 / 100;

    String result = BigDecimal.valueOf(total).toPlainString();

    System.out.println(result);

  } main {

    Scanner sc = new Scanner(System.in);
    long a = sc.nextLong();
    float b = sc.nextFloat();

    int b2 = Math.round(b * 100);

    long total = a * b2 / 100;

    String result = BigDecimal.valueOf(total).toPlainString();

    System.out.println(result);

  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long a = sc.nextLong(); a sc.nextLong() sc.nextLong sc float b = sc.nextFloat(); b sc.nextFloat() sc.nextFloat sc int b2 = Math.round(b * 100); b2 Math.round(b * 100) Math.round Math b * 100 b 100 long total = a * b2 / 100; total a * b2 / 100 a * b2 a b2 100 String result = BigDecimal.valueOf(total).toPlainString(); result BigDecimal.valueOf(total).toPlainString() BigDecimal.valueOf(total).toPlainString BigDecimal.valueOf(total) BigDecimal.valueOf BigDecimal total System.out.println(result) System.out.println System.out System System.out result String[] args args public class Main {
  public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);
    long a = sc.nextLong();
    float b = sc.nextFloat();

    int b2 = Math.round(b * 100);

    long total = a * b2 / 100;

    String result = BigDecimal.valueOf(total).toPlainString();

    System.out.println(result);

  }
} public class Main {
  public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);
    long a = sc.nextLong();
    float b = sc.nextFloat();

    int b2 = Math.round(b * 100);

    long total = a * b2 / 100;

    String result = BigDecimal.valueOf(total).toPlainString();

    System.out.println(result);

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

public class Main {
  public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);
    long a = sc.nextLong();
    float b = sc.nextFloat();

    int b2 = Math.round(b * 100);

    long total = a * b2 / 100;

    String result = BigDecimal.valueOf(total).toPlainString();

    System.out.println(result);

  }
}
