import java.math.BigDecimal;
import java.util.Scanner;
public class Main {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		
		long A = scan.nextLong();
		double B = scan.nextDouble();
		
		BigDecimal a = new BigDecimal(String.valueOf(A));
		BigDecimal b = new BigDecimal(String.valueOf(B));
		BigDecimal multi =a.multiply(b);
		BigDecimal multi1 = multi.setScale(0, BigDecimal.ROUND_DOWN);
		
		System.out.println(multi1);

	}

} import java.math.BigDecimal; BigDecimal java.math import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		
		long A = scan.nextLong();
		double B = scan.nextDouble();
		
		BigDecimal a = new BigDecimal(String.valueOf(A));
		BigDecimal b = new BigDecimal(String.valueOf(B));
		BigDecimal multi =a.multiply(b);
		BigDecimal multi1 = multi.setScale(0, BigDecimal.ROUND_DOWN);
		
		System.out.println(multi1);

	}

} Main public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		
		long A = scan.nextLong();
		double B = scan.nextDouble();
		
		BigDecimal a = new BigDecimal(String.valueOf(A));
		BigDecimal b = new BigDecimal(String.valueOf(B));
		BigDecimal multi =a.multiply(b);
		BigDecimal multi1 = multi.setScale(0, BigDecimal.ROUND_DOWN);
		
		System.out.println(multi1);

	} main {
		Scanner scan = new Scanner(System.in);
		
		long A = scan.nextLong();
		double B = scan.nextDouble();
		
		BigDecimal a = new BigDecimal(String.valueOf(A));
		BigDecimal b = new BigDecimal(String.valueOf(B));
		BigDecimal multi =a.multiply(b);
		BigDecimal multi1 = multi.setScale(0, BigDecimal.ROUND_DOWN);
		
		System.out.println(multi1);

	} Scanner scan = new Scanner(System.in); scan new Scanner(System.in) long A = scan.nextLong(); A scan.nextLong() scan.nextLong scan double B = scan.nextDouble(); B scan.nextDouble() scan.nextDouble scan BigDecimal a = new BigDecimal(String.valueOf(A)); a new BigDecimal(String.valueOf(A)) BigDecimal b = new BigDecimal(String.valueOf(B)); b new BigDecimal(String.valueOf(B)) BigDecimal multi =a.multiply(b); multi a.multiply(b) a.multiply a b BigDecimal multi1 = multi.setScale(0, BigDecimal.ROUND_DOWN); multi1 multi.setScale(0, BigDecimal.ROUND_DOWN) multi.setScale multi 0 BigDecimal.ROUND_DOWN BigDecimal BigDecimal.ROUND_DOWN System.out.println(multi1) System.out.println System.out System System.out multi1 String[] args args public class Main {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		
		long A = scan.nextLong();
		double B = scan.nextDouble();
		
		BigDecimal a = new BigDecimal(String.valueOf(A));
		BigDecimal b = new BigDecimal(String.valueOf(B));
		BigDecimal multi =a.multiply(b);
		BigDecimal multi1 = multi.setScale(0, BigDecimal.ROUND_DOWN);
		
		System.out.println(multi1);

	}

} public class Main {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		
		long A = scan.nextLong();
		double B = scan.nextDouble();
		
		BigDecimal a = new BigDecimal(String.valueOf(A));
		BigDecimal b = new BigDecimal(String.valueOf(B));
		BigDecimal multi =a.multiply(b);
		BigDecimal multi1 = multi.setScale(0, BigDecimal.ROUND_DOWN);
		
		System.out.println(multi1);

	}

} Main
import java.math.BigDecimal;
import java.util.Scanner;
public class Main {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		
		long A = scan.nextLong();
		double B = scan.nextDouble();
		
		BigDecimal a = new BigDecimal(String.valueOf(A));
		BigDecimal b = new BigDecimal(String.valueOf(B));
		BigDecimal multi =a.multiply(b);
		BigDecimal multi1 = multi.setScale(0, BigDecimal.ROUND_DOWN);
		
		System.out.println(multi1);

	}

}
