import java.util.Scanner;
import java.util.ArrayList;
 
public class Main {
  final static int max = 100;
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
      int i = 0;
      String N;     
        long A = scan.nextLong();
        double B = scan.nextDouble();
     //   System.out.println(a[i]);
        cal(A,B);
        scan.close();
    }
  
  public static void cal(long a,double b){
     long s = 0;
     long bb;
    bb = Math.round(b*100);
     s = a*bb/100;
     System.out.println(s);
  }
} import java.util.Scanner; Scanner java.util import java.util.ArrayList; ArrayList java.util public class Main {
  final static int max = 100;
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
      int i = 0;
      String N;     
        long A = scan.nextLong();
        double B = scan.nextDouble();
     //   System.out.println(a[i]);
        cal(A,B);
        scan.close();
    }
  
  public static void cal(long a,double b){
     long s = 0;
     long bb;
    bb = Math.round(b*100);
     s = a*bb/100;
     System.out.println(s);
  }
} Main final static int max = 100; max 100 public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
      int i = 0;
      String N;     
        long A = scan.nextLong();
        double B = scan.nextDouble();
     //   System.out.println(a[i]);
        cal(A,B);
        scan.close();
    } main {
        Scanner scan = new Scanner(System.in);
      int i = 0;
      String N;     
        long A = scan.nextLong();
        double B = scan.nextDouble();
     //   System.out.println(a[i]);
        cal(A,B);
        scan.close();
    } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int i = 0; i 0 String N; N long A = scan.nextLong(); A scan.nextLong() scan.nextLong scan double B = scan.nextDouble(); B scan.nextDouble() scan.nextDouble scan cal(A,B) cal A B scan.close() scan.close scan String[] args args public static void cal(long a,double b){
     long s = 0;
     long bb;
    bb = Math.round(b*100);
     s = a*bb/100;
     System.out.println(s);
  } cal {
     long s = 0;
     long bb;
    bb = Math.round(b*100);
     s = a*bb/100;
     System.out.println(s);
  } long s = 0; s 0 long bb; bb bb = Math.round(b*100) bb Math.round(b*100) Math.round Math b*100 b 100 s = a*bb/100 s a*bb/100 a*bb a bb 100 System.out.println(s) System.out.println System.out System System.out s long a a double b b public class Main {
  final static int max = 100;
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
      int i = 0;
      String N;     
        long A = scan.nextLong();
        double B = scan.nextDouble();
     //   System.out.println(a[i]);
        cal(A,B);
        scan.close();
    }
  
  public static void cal(long a,double b){
     long s = 0;
     long bb;
    bb = Math.round(b*100);
     s = a*bb/100;
     System.out.println(s);
  }
} public class Main {
  final static int max = 100;
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
      int i = 0;
      String N;     
        long A = scan.nextLong();
        double B = scan.nextDouble();
     //   System.out.println(a[i]);
        cal(A,B);
        scan.close();
    }
  
  public static void cal(long a,double b){
     long s = 0;
     long bb;
    bb = Math.round(b*100);
     s = a*bb/100;
     System.out.println(s);
  }
} Main
import java.util.Scanner;
import java.util.ArrayList;
 
public class Main {
  final static int max = 100;
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
      int i = 0;
      String N;     
        long A = scan.nextLong();
        double B = scan.nextDouble();
     //   System.out.println(a[i]);
        cal(A,B);
        scan.close();
    }
  
  public static void cal(long a,double b){
     long s = 0;
     long bb;
    bb = Math.round(b*100);
     s = a*bb/100;
     System.out.println(s);
  }
}