import java.math.BigDecimal;
import java.util.*;

public class Main {

    public static void main(String[] args) {
        exec();
    }

    static void exec() {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        double m = sc.nextDouble();

        BigDecimal b = BigDecimal.valueOf(n);
        BigDecimal c = BigDecimal.valueOf(m);
        System.out.println(b.multiply(c).setScale(0, BigDecimal.ROUND_DOWN));
    }
} import java.math.BigDecimal; BigDecimal java.math import java.util.*; util.* java public class Main {

    public static void main(String[] args) {
        exec();
    }

    static void exec() {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        double m = sc.nextDouble();

        BigDecimal b = BigDecimal.valueOf(n);
        BigDecimal c = BigDecimal.valueOf(m);
        System.out.println(b.multiply(c).setScale(0, BigDecimal.ROUND_DOWN));
    }
} Main public static void main(String[] args) {
        exec();
    } main {
        exec();
    } exec() exec String[] args args static void exec() {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        double m = sc.nextDouble();

        BigDecimal b = BigDecimal.valueOf(n);
        BigDecimal c = BigDecimal.valueOf(m);
        System.out.println(b.multiply(c).setScale(0, BigDecimal.ROUND_DOWN));
    } exec {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        double m = sc.nextDouble();

        BigDecimal b = BigDecimal.valueOf(n);
        BigDecimal c = BigDecimal.valueOf(m);
        System.out.println(b.multiply(c).setScale(0, BigDecimal.ROUND_DOWN));
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc double m = sc.nextDouble(); m sc.nextDouble() sc.nextDouble sc BigDecimal b = BigDecimal.valueOf(n); b BigDecimal.valueOf(n) BigDecimal.valueOf BigDecimal n BigDecimal c = BigDecimal.valueOf(m); c BigDecimal.valueOf(m) BigDecimal.valueOf BigDecimal m System.out.println(b.multiply(c).setScale(0, BigDecimal.ROUND_DOWN)) System.out.println System.out System System.out b.multiply(c).setScale(0, BigDecimal.ROUND_DOWN) b.multiply(c).setScale b.multiply(c) b.multiply b c 0 BigDecimal.ROUND_DOWN BigDecimal BigDecimal.ROUND_DOWN public class Main {

    public static void main(String[] args) {
        exec();
    }

    static void exec() {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        double m = sc.nextDouble();

        BigDecimal b = BigDecimal.valueOf(n);
        BigDecimal c = BigDecimal.valueOf(m);
        System.out.println(b.multiply(c).setScale(0, BigDecimal.ROUND_DOWN));
    }
} public class Main {

    public static void main(String[] args) {
        exec();
    }

    static void exec() {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        double m = sc.nextDouble();

        BigDecimal b = BigDecimal.valueOf(n);
        BigDecimal c = BigDecimal.valueOf(m);
        System.out.println(b.multiply(c).setScale(0, BigDecimal.ROUND_DOWN));
    }
} Main
import java.math.BigDecimal;
import java.util.*;

public class Main {

    public static void main(String[] args) {
        exec();
    }

    static void exec() {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        double m = sc.nextDouble();

        BigDecimal b = BigDecimal.valueOf(n);
        BigDecimal c = BigDecimal.valueOf(m);
        System.out.println(b.multiply(c).setScale(0, BigDecimal.ROUND_DOWN));
    }
}