import java.util.*;
import java.math.*;
 
public class Main {
    public static void main(String[] args) throws Exception {
        
        Scanner sc = new Scanner(System.in);
         
        long A = sc.nextLong();
      
      	double B = sc.nextDouble();
      		
      	BigDecimal bd_A = new BigDecimal(A);
      	BigDecimal bd_B = new BigDecimal(String.valueOf(B));
	
      	BigDecimal bd_C = bd_A.multiply(bd_B);
       
      	long l = bd_C.longValue();

      	System.out.println(l);
      

    }
} import java.util.*; util.* java import java.math.*; math.* java public class Main {
    public static void main(String[] args) throws Exception {
        
        Scanner sc = new Scanner(System.in);
         
        long A = sc.nextLong();
      
      	double B = sc.nextDouble();
      		
      	BigDecimal bd_A = new BigDecimal(A);
      	BigDecimal bd_B = new BigDecimal(String.valueOf(B));
	
      	BigDecimal bd_C = bd_A.multiply(bd_B);
       
      	long l = bd_C.longValue();

      	System.out.println(l);
      

    }
} Main public static void main(String[] args) throws Exception {
        
        Scanner sc = new Scanner(System.in);
         
        long A = sc.nextLong();
      
      	double B = sc.nextDouble();
      		
      	BigDecimal bd_A = new BigDecimal(A);
      	BigDecimal bd_B = new BigDecimal(String.valueOf(B));
	
      	BigDecimal bd_C = bd_A.multiply(bd_B);
       
      	long l = bd_C.longValue();

      	System.out.println(l);
      

    } main {
        
        Scanner sc = new Scanner(System.in);
         
        long A = sc.nextLong();
      
      	double B = sc.nextDouble();
      		
      	BigDecimal bd_A = new BigDecimal(A);
      	BigDecimal bd_B = new BigDecimal(String.valueOf(B));
	
      	BigDecimal bd_C = bd_A.multiply(bd_B);
       
      	long l = bd_C.longValue();

      	System.out.println(l);
      

    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long A = sc.nextLong(); A sc.nextLong() sc.nextLong sc double B = sc.nextDouble(); B sc.nextDouble() sc.nextDouble sc BigDecimal bd_A = new BigDecimal(A); bd_A new BigDecimal(A) BigDecimal bd_B = new BigDecimal(String.valueOf(B)); bd_B new BigDecimal(String.valueOf(B)) BigDecimal bd_C = bd_A.multiply(bd_B); bd_C bd_A.multiply(bd_B) bd_A.multiply bd_A bd_B long l = bd_C.longValue(); l bd_C.longValue() bd_C.longValue bd_C System.out.println(l) System.out.println System.out System System.out l String[] args args public class Main {
    public static void main(String[] args) throws Exception {
        
        Scanner sc = new Scanner(System.in);
         
        long A = sc.nextLong();
      
      	double B = sc.nextDouble();
      		
      	BigDecimal bd_A = new BigDecimal(A);
      	BigDecimal bd_B = new BigDecimal(String.valueOf(B));
	
      	BigDecimal bd_C = bd_A.multiply(bd_B);
       
      	long l = bd_C.longValue();

      	System.out.println(l);
      

    }
} public class Main {
    public static void main(String[] args) throws Exception {
        
        Scanner sc = new Scanner(System.in);
         
        long A = sc.nextLong();
      
      	double B = sc.nextDouble();
      		
      	BigDecimal bd_A = new BigDecimal(A);
      	BigDecimal bd_B = new BigDecimal(String.valueOf(B));
	
      	BigDecimal bd_C = bd_A.multiply(bd_B);
       
      	long l = bd_C.longValue();

      	System.out.println(l);
      

    }
} Main
import java.util.*;
import java.math.*;
 
public class Main {
    public static void main(String[] args) throws Exception {
        
        Scanner sc = new Scanner(System.in);
         
        long A = sc.nextLong();
      
      	double B = sc.nextDouble();
      		
      	BigDecimal bd_A = new BigDecimal(A);
      	BigDecimal bd_B = new BigDecimal(String.valueOf(B));
	
      	BigDecimal bd_C = bd_A.multiply(bd_B);
       
      	long l = bd_C.longValue();

      	System.out.println(l);
      

    }
}