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

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String[] line = sc.nextLine().split(" ", 0);

		BigDecimal a = new BigDecimal(line[0]);
		BigDecimal b = new BigDecimal(line[1]).multiply(BigDecimal.valueOf(100));
		BigDecimal ans = a.multiply(b).divide(BigDecimal.valueOf(100));

		System.out.println(ans.setScale(0, RoundingMode.DOWN));
	}
} import java.math.BigDecimal; BigDecimal java.math import java.math.RoundingMode; RoundingMode java.math import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String[] line = sc.nextLine().split(" ", 0);

		BigDecimal a = new BigDecimal(line[0]);
		BigDecimal b = new BigDecimal(line[1]).multiply(BigDecimal.valueOf(100));
		BigDecimal ans = a.multiply(b).divide(BigDecimal.valueOf(100));

		System.out.println(ans.setScale(0, RoundingMode.DOWN));
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String[] line = sc.nextLine().split(" ", 0);

		BigDecimal a = new BigDecimal(line[0]);
		BigDecimal b = new BigDecimal(line[1]).multiply(BigDecimal.valueOf(100));
		BigDecimal ans = a.multiply(b).divide(BigDecimal.valueOf(100));

		System.out.println(ans.setScale(0, RoundingMode.DOWN));
	} main {
		Scanner sc = new Scanner(System.in);
		String[] line = sc.nextLine().split(" ", 0);

		BigDecimal a = new BigDecimal(line[0]);
		BigDecimal b = new BigDecimal(line[1]).multiply(BigDecimal.valueOf(100));
		BigDecimal ans = a.multiply(b).divide(BigDecimal.valueOf(100));

		System.out.println(ans.setScale(0, RoundingMode.DOWN));
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String[] line = sc.nextLine().split(" ", 0); line sc.nextLine().split(" ", 0) sc.nextLine().split sc.nextLine() sc.nextLine sc " " 0 BigDecimal a = new BigDecimal(line[0]); a new BigDecimal(line[0]) BigDecimal b = new BigDecimal(line[1]).multiply(BigDecimal.valueOf(100)); b new BigDecimal(line[1]).multiply(BigDecimal.valueOf(100)) new BigDecimal(line[1]).multiply new BigDecimal(line[1]) BigDecimal.valueOf(100) BigDecimal.valueOf BigDecimal 100 BigDecimal ans = a.multiply(b).divide(BigDecimal.valueOf(100)); ans a.multiply(b).divide(BigDecimal.valueOf(100)) a.multiply(b).divide a.multiply(b) a.multiply a b BigDecimal.valueOf(100) BigDecimal.valueOf BigDecimal 100 System.out.println(ans.setScale(0, RoundingMode.DOWN)) System.out.println System.out System System.out ans.setScale(0, RoundingMode.DOWN) ans.setScale ans 0 RoundingMode.DOWN RoundingMode RoundingMode.DOWN String[] args args public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String[] line = sc.nextLine().split(" ", 0);

		BigDecimal a = new BigDecimal(line[0]);
		BigDecimal b = new BigDecimal(line[1]).multiply(BigDecimal.valueOf(100));
		BigDecimal ans = a.multiply(b).divide(BigDecimal.valueOf(100));

		System.out.println(ans.setScale(0, RoundingMode.DOWN));
	}
} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String[] line = sc.nextLine().split(" ", 0);

		BigDecimal a = new BigDecimal(line[0]);
		BigDecimal b = new BigDecimal(line[1]).multiply(BigDecimal.valueOf(100));
		BigDecimal ans = a.multiply(b).divide(BigDecimal.valueOf(100));

		System.out.println(ans.setScale(0, RoundingMode.DOWN));
	}
} Main
import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String[] line = sc.nextLine().split(" ", 0);

		BigDecimal a = new BigDecimal(line[0]);
		BigDecimal b = new BigDecimal(line[1]).multiply(BigDecimal.valueOf(100));
		BigDecimal ans = a.multiply(b).divide(BigDecimal.valueOf(100));

		System.out.println(ans.setScale(0, RoundingMode.DOWN));
	}
}