import java.util.*;
import java.math.BigDecimal;
public class Main {
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
      long A=sc.nextLong();
      double B=sc.nextDouble();
      BigDecimal a=BigDecimal.valueOf(A);
      BigDecimal b=BigDecimal.valueOf(B);
      BigDecimal c=a.multiply(b);
      BigDecimal x=c.setScale(0,BigDecimal.ROUND_DOWN);
      System.out.println(x);
	}
} import java.util.*; util.* java import java.math.BigDecimal; BigDecimal java.math public class Main {
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
      long A=sc.nextLong();
      double B=sc.nextDouble();
      BigDecimal a=BigDecimal.valueOf(A);
      BigDecimal b=BigDecimal.valueOf(B);
      BigDecimal c=a.multiply(b);
      BigDecimal x=c.setScale(0,BigDecimal.ROUND_DOWN);
      System.out.println(x);
	}
} Main public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
      long A=sc.nextLong();
      double B=sc.nextDouble();
      BigDecimal a=BigDecimal.valueOf(A);
      BigDecimal b=BigDecimal.valueOf(B);
      BigDecimal c=a.multiply(b);
      BigDecimal x=c.setScale(0,BigDecimal.ROUND_DOWN);
      System.out.println(x);
	} main {
		Scanner sc=new Scanner(System.in);
      long A=sc.nextLong();
      double B=sc.nextDouble();
      BigDecimal a=BigDecimal.valueOf(A);
      BigDecimal b=BigDecimal.valueOf(B);
      BigDecimal c=a.multiply(b);
      BigDecimal x=c.setScale(0,BigDecimal.ROUND_DOWN);
      System.out.println(x);
	} 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 a=BigDecimal.valueOf(A); a BigDecimal.valueOf(A) BigDecimal.valueOf BigDecimal A BigDecimal b=BigDecimal.valueOf(B); b BigDecimal.valueOf(B) BigDecimal.valueOf BigDecimal B BigDecimal c=a.multiply(b); c a.multiply(b) a.multiply a b BigDecimal x=c.setScale(0,BigDecimal.ROUND_DOWN); x c.setScale(0,BigDecimal.ROUND_DOWN) c.setScale c 0 BigDecimal.ROUND_DOWN BigDecimal BigDecimal.ROUND_DOWN System.out.println(x) System.out.println System.out System System.out x String[] args args public class Main {
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
      long A=sc.nextLong();
      double B=sc.nextDouble();
      BigDecimal a=BigDecimal.valueOf(A);
      BigDecimal b=BigDecimal.valueOf(B);
      BigDecimal c=a.multiply(b);
      BigDecimal x=c.setScale(0,BigDecimal.ROUND_DOWN);
      System.out.println(x);
	}
} public class Main {
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
      long A=sc.nextLong();
      double B=sc.nextDouble();
      BigDecimal a=BigDecimal.valueOf(A);
      BigDecimal b=BigDecimal.valueOf(B);
      BigDecimal c=a.multiply(b);
      BigDecimal x=c.setScale(0,BigDecimal.ROUND_DOWN);
      System.out.println(x);
	}
} Main
import java.util.*;
import java.math.BigDecimal;
public class Main {
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
      long A=sc.nextLong();
      double B=sc.nextDouble();
      BigDecimal a=BigDecimal.valueOf(A);
      BigDecimal b=BigDecimal.valueOf(B);
      BigDecimal c=a.multiply(b);
      BigDecimal x=c.setScale(0,BigDecimal.ROUND_DOWN);
      System.out.println(x);
	}
}