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

public class Main {

    Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        new Main().run();
    }

    void run() {

        long a = sc.nextLong();
        double b = sc.nextDouble();
        long lb = 0;
        for (int i=0; i<1000; i++) {
            double tmp = (double)i / (double)100;
            if (tmp==b) {
                lb = i;
            }
        }

//        System.out.println(lb);

        System.out.println((a*lb)/(long)100);
    }
} import java.math.BigDecimal; BigDecimal java.math import java.util.*; util.* java public class Main {

    Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        new Main().run();
    }

    void run() {

        long a = sc.nextLong();
        double b = sc.nextDouble();
        long lb = 0;
        for (int i=0; i<1000; i++) {
            double tmp = (double)i / (double)100;
            if (tmp==b) {
                lb = i;
            }
        }

//        System.out.println(lb);

        System.out.println((a*lb)/(long)100);
    }
} Main Scanner sc = new Scanner(System.in); sc new Scanner(System.in) public static void main(String[] args) {
        new Main().run();
    } main {
        new Main().run();
    } new Main().run() new Main().run new Main() String[] args args void run() {

        long a = sc.nextLong();
        double b = sc.nextDouble();
        long lb = 0;
        for (int i=0; i<1000; i++) {
            double tmp = (double)i / (double)100;
            if (tmp==b) {
                lb = i;
            }
        }

//        System.out.println(lb);

        System.out.println((a*lb)/(long)100);
    } run {

        long a = sc.nextLong();
        double b = sc.nextDouble();
        long lb = 0;
        for (int i=0; i<1000; i++) {
            double tmp = (double)i / (double)100;
            if (tmp==b) {
                lb = i;
            }
        }

//        System.out.println(lb);

        System.out.println((a*lb)/(long)100);
    } long a = sc.nextLong(); a sc.nextLong() sc.nextLong sc double b = sc.nextDouble(); b sc.nextDouble() sc.nextDouble sc long lb = 0; lb 0 for (int i=0; i<1000; i++) {
            double tmp = (double)i / (double)100;
            if (tmp==b) {
                lb = i;
            }
        } int i=0; int i=0; i 0 i<1000 i 1000 i++ i++ i {
            double tmp = (double)i / (double)100;
            if (tmp==b) {
                lb = i;
            }
        } {
            double tmp = (double)i / (double)100;
            if (tmp==b) {
                lb = i;
            }
        } double tmp = (double)i / (double)100; tmp (double)i / (double)100 (double)i (double)100 if (tmp==b) {
                lb = i;
            } tmp==b tmp b {
                lb = i;
            } lb = i lb i System.out.println((a*lb)/(long)100) System.out.println System.out System System.out (a*lb)/(long)100 (a*lb) a lb (long)100 public class Main {

    Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        new Main().run();
    }

    void run() {

        long a = sc.nextLong();
        double b = sc.nextDouble();
        long lb = 0;
        for (int i=0; i<1000; i++) {
            double tmp = (double)i / (double)100;
            if (tmp==b) {
                lb = i;
            }
        }

//        System.out.println(lb);

        System.out.println((a*lb)/(long)100);
    }
} public class Main {

    Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        new Main().run();
    }

    void run() {

        long a = sc.nextLong();
        double b = sc.nextDouble();
        long lb = 0;
        for (int i=0; i<1000; i++) {
            double tmp = (double)i / (double)100;
            if (tmp==b) {
                lb = i;
            }
        }

//        System.out.println(lb);

        System.out.println((a*lb)/(long)100);
    }
} Main
import java.math.BigDecimal;
import java.util.*;

public class Main {

    Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        new Main().run();
    }

    void run() {

        long a = sc.nextLong();
        double b = sc.nextDouble();
        long lb = 0;
        for (int i=0; i<1000; i++) {
            double tmp = (double)i / (double)100;
            if (tmp==b) {
                lb = i;
            }
        }

//        System.out.println(lb);

        System.out.println((a*lb)/(long)100);
    }
}
