import java.math.BigDecimal;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long a = sc.nextLong();
		double b = sc.nextDouble();
		
		BigDecimal result = BigDecimal.valueOf(a).multiply(BigDecimal.valueOf(b));
		System.out.println(result.longValue());
	}

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

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long a = sc.nextLong();
		double b = sc.nextDouble();
		
		BigDecimal result = BigDecimal.valueOf(a).multiply(BigDecimal.valueOf(b));
		System.out.println(result.longValue());
	}

} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long a = sc.nextLong();
		double b = sc.nextDouble();
		
		BigDecimal result = BigDecimal.valueOf(a).multiply(BigDecimal.valueOf(b));
		System.out.println(result.longValue());
	} main {
		Scanner sc = new Scanner(System.in);
		long a = sc.nextLong();
		double b = sc.nextDouble();
		
		BigDecimal result = BigDecimal.valueOf(a).multiply(BigDecimal.valueOf(b));
		System.out.println(result.longValue());
	} 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 result = BigDecimal.valueOf(a).multiply(BigDecimal.valueOf(b)); result BigDecimal.valueOf(a).multiply(BigDecimal.valueOf(b)) BigDecimal.valueOf(a).multiply BigDecimal.valueOf(a) BigDecimal.valueOf BigDecimal a BigDecimal.valueOf(b) BigDecimal.valueOf BigDecimal b System.out.println(result.longValue()) System.out.println System.out System System.out result.longValue() result.longValue result 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 result = BigDecimal.valueOf(a).multiply(BigDecimal.valueOf(b));
		System.out.println(result.longValue());
	}

} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long a = sc.nextLong();
		double b = sc.nextDouble();
		
		BigDecimal result = BigDecimal.valueOf(a).multiply(BigDecimal.valueOf(b));
		System.out.println(result.longValue());
	}

} Main
import java.math.BigDecimal;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long a = sc.nextLong();
		double b = sc.nextDouble();
		
		BigDecimal result = BigDecimal.valueOf(a).multiply(BigDecimal.valueOf(b));
		System.out.println(result.longValue());
	}

}
