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

public class Main {

    public static final int MOD = 1000000007;

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long a = Long.parseLong(sc.next());
        String b = sc.next();
        BigDecimal A = new BigDecimal(a);
        BigDecimal B = new BigDecimal(b);
        BigDecimal c = A.multiply(B);
        System.out.println(c.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 final int MOD = 1000000007;

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long a = Long.parseLong(sc.next());
        String b = sc.next();
        BigDecimal A = new BigDecimal(a);
        BigDecimal B = new BigDecimal(b);
        BigDecimal c = A.multiply(B);
        System.out.println(c.setScale(0, RoundingMode.DOWN));
    }
} Main public static final int MOD = 1000000007; MOD 1000000007 public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long a = Long.parseLong(sc.next());
        String b = sc.next();
        BigDecimal A = new BigDecimal(a);
        BigDecimal B = new BigDecimal(b);
        BigDecimal c = A.multiply(B);
        System.out.println(c.setScale(0, RoundingMode.DOWN));
    } main {
        Scanner sc = new Scanner(System.in);
        long a = Long.parseLong(sc.next());
        String b = sc.next();
        BigDecimal A = new BigDecimal(a);
        BigDecimal B = new BigDecimal(b);
        BigDecimal c = A.multiply(B);
        System.out.println(c.setScale(0, RoundingMode.DOWN));
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long a = Long.parseLong(sc.next()); a Long.parseLong(sc.next()) Long.parseLong Long sc.next() sc.next sc String b = sc.next(); b sc.next() sc.next sc BigDecimal A = new BigDecimal(a); A new BigDecimal(a) BigDecimal B = new BigDecimal(b); B new BigDecimal(b) BigDecimal c = A.multiply(B); c A.multiply(B) A.multiply A B System.out.println(c.setScale(0, RoundingMode.DOWN)) System.out.println System.out System System.out c.setScale(0, RoundingMode.DOWN) c.setScale c 0 RoundingMode.DOWN RoundingMode RoundingMode.DOWN String[] args args public class Main {

    public static final int MOD = 1000000007;

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long a = Long.parseLong(sc.next());
        String b = sc.next();
        BigDecimal A = new BigDecimal(a);
        BigDecimal B = new BigDecimal(b);
        BigDecimal c = A.multiply(B);
        System.out.println(c.setScale(0, RoundingMode.DOWN));
    }
} public class Main {

    public static final int MOD = 1000000007;

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long a = Long.parseLong(sc.next());
        String b = sc.next();
        BigDecimal A = new BigDecimal(a);
        BigDecimal B = new BigDecimal(b);
        BigDecimal c = A.multiply(B);
        System.out.println(c.setScale(0, RoundingMode.DOWN));
    }
} Main
import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.Scanner;

public class Main {

    public static final int MOD = 1000000007;

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long a = Long.parseLong(sc.next());
        String b = sc.next();
        BigDecimal A = new BigDecimal(a);
        BigDecimal B = new BigDecimal(b);
        BigDecimal c = A.multiply(B);
        System.out.println(c.setScale(0, RoundingMode.DOWN));
    }
}