import java.util.*;
import java.io.PrintWriter;
import java.math.*;
public class Main{
	public static void main(String[] args){
		Scanner sc=new Scanner(System.in);
		BigDecimal a=BigDecimal.valueOf(sc.nextLong());
		BigDecimal b=BigDecimal.valueOf(sc.nextDouble());
	
		System.out.println(a.multiply(b).longValue());
	}
} import java.util.*; util.* java import java.io.PrintWriter; PrintWriter java.io import java.math.*; math.* java public class Main{
	public static void main(String[] args){
		Scanner sc=new Scanner(System.in);
		BigDecimal a=BigDecimal.valueOf(sc.nextLong());
		BigDecimal b=BigDecimal.valueOf(sc.nextDouble());
	
		System.out.println(a.multiply(b).longValue());
	}
} Main public static void main(String[] args){
		Scanner sc=new Scanner(System.in);
		BigDecimal a=BigDecimal.valueOf(sc.nextLong());
		BigDecimal b=BigDecimal.valueOf(sc.nextDouble());
	
		System.out.println(a.multiply(b).longValue());
	} main {
		Scanner sc=new Scanner(System.in);
		BigDecimal a=BigDecimal.valueOf(sc.nextLong());
		BigDecimal b=BigDecimal.valueOf(sc.nextDouble());
	
		System.out.println(a.multiply(b).longValue());
	} Scanner sc=new Scanner(System.in); sc new Scanner(System.in) BigDecimal a=BigDecimal.valueOf(sc.nextLong()); a BigDecimal.valueOf(sc.nextLong()) BigDecimal.valueOf BigDecimal sc.nextLong() sc.nextLong sc BigDecimal b=BigDecimal.valueOf(sc.nextDouble()); b BigDecimal.valueOf(sc.nextDouble()) BigDecimal.valueOf BigDecimal sc.nextDouble() sc.nextDouble sc System.out.println(a.multiply(b).longValue()) System.out.println System.out System System.out a.multiply(b).longValue() a.multiply(b).longValue a.multiply(b) a.multiply a b String[] args args public class Main{
	public static void main(String[] args){
		Scanner sc=new Scanner(System.in);
		BigDecimal a=BigDecimal.valueOf(sc.nextLong());
		BigDecimal b=BigDecimal.valueOf(sc.nextDouble());
	
		System.out.println(a.multiply(b).longValue());
	}
} public class Main{
	public static void main(String[] args){
		Scanner sc=new Scanner(System.in);
		BigDecimal a=BigDecimal.valueOf(sc.nextLong());
		BigDecimal b=BigDecimal.valueOf(sc.nextDouble());
	
		System.out.println(a.multiply(b).longValue());
	}
} Main
import java.util.*;
import java.io.PrintWriter;
import java.math.*;
public class Main{
	public static void main(String[] args){
		Scanner sc=new Scanner(System.in);
		BigDecimal a=BigDecimal.valueOf(sc.nextLong());
		BigDecimal b=BigDecimal.valueOf(sc.nextDouble());
	
		System.out.println(a.multiply(b).longValue());
	}
}
