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

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		BigDecimal a = sc.nextBigDecimal();
		BigDecimal b= sc.nextBigDecimal();
		BigDecimal c = b.multiply(a);
		long d = c.longValue();
		System.out.println(d);
		
		

	}

} 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);
		BigDecimal a = sc.nextBigDecimal();
		BigDecimal b= sc.nextBigDecimal();
		BigDecimal c = b.multiply(a);
		long d = c.longValue();
		System.out.println(d);
		
		

	}

} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		BigDecimal a = sc.nextBigDecimal();
		BigDecimal b= sc.nextBigDecimal();
		BigDecimal c = b.multiply(a);
		long d = c.longValue();
		System.out.println(d);
		
		

	} main {
		Scanner sc = new Scanner(System.in);
		BigDecimal a = sc.nextBigDecimal();
		BigDecimal b= sc.nextBigDecimal();
		BigDecimal c = b.multiply(a);
		long d = c.longValue();
		System.out.println(d);
		
		

	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) BigDecimal a = sc.nextBigDecimal(); a sc.nextBigDecimal() sc.nextBigDecimal sc BigDecimal b= sc.nextBigDecimal(); b sc.nextBigDecimal() sc.nextBigDecimal sc BigDecimal c = b.multiply(a); c b.multiply(a) b.multiply b a long d = c.longValue(); d c.longValue() c.longValue c System.out.println(d) System.out.println System.out System System.out d String[] args args public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		BigDecimal a = sc.nextBigDecimal();
		BigDecimal b= sc.nextBigDecimal();
		BigDecimal c = b.multiply(a);
		long d = c.longValue();
		System.out.println(d);
		
		

	}

} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		BigDecimal a = sc.nextBigDecimal();
		BigDecimal b= sc.nextBigDecimal();
		BigDecimal c = b.multiply(a);
		long d = c.longValue();
		System.out.println(d);
		
		

	}

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

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		BigDecimal a = sc.nextBigDecimal();
		BigDecimal b= sc.nextBigDecimal();
		BigDecimal c = b.multiply(a);
		long d = c.longValue();
		System.out.println(d);
		
		

	}

}
