import java.util.*;
import java.io.*;
 
class Main{
  public static void main(String[]args){
    Scanner sc = new Scanner(System.in);
    long n = sc.nextLong();
    double m = sc.nextLong();
    long result = (long)Math.round(m*100);
    
    result = result*n/100;
    
    System.out.println(result);
  }
} import java.util.*; util.* java import java.io.*; io.* java class Main{
  public static void main(String[]args){
    Scanner sc = new Scanner(System.in);
    long n = sc.nextLong();
    double m = sc.nextLong();
    long result = (long)Math.round(m*100);
    
    result = result*n/100;
    
    System.out.println(result);
  }
} Main public static void main(String[]args){
    Scanner sc = new Scanner(System.in);
    long n = sc.nextLong();
    double m = sc.nextLong();
    long result = (long)Math.round(m*100);
    
    result = result*n/100;
    
    System.out.println(result);
  } main {
    Scanner sc = new Scanner(System.in);
    long n = sc.nextLong();
    double m = sc.nextLong();
    long result = (long)Math.round(m*100);
    
    result = result*n/100;
    
    System.out.println(result);
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc double m = sc.nextLong(); m sc.nextLong() sc.nextLong sc long result = (long)Math.round(m*100); result (long)Math.round(m*100) Math.round Math m*100 m 100 result = result*n/100 result result*n/100 result*n result n 100 System.out.println(result) System.out.println System.out System System.out result String[]args args
import java.util.*;
import java.io.*;
 
class Main{
  public static void main(String[]args){
    Scanner sc = new Scanner(System.in);
    long n = sc.nextLong();
    double m = sc.nextLong();
    long result = (long)Math.round(m*100);
    
    result = result*n/100;
    
    System.out.println(result);
  }
}