
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        final long A = sc.nextLong();
        String B = sc.next();
        int b_x = Integer.valueOf(B.substring(0, 1)), b_y = Integer.parseInt(B.substring(2));
        long a_x = A * b_x;
        long a_y = A * b_y / 100;
        System.out.println(a_x + a_y);
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        final long A = sc.nextLong();
        String B = sc.next();
        int b_x = Integer.valueOf(B.substring(0, 1)), b_y = Integer.parseInt(B.substring(2));
        long a_x = A * b_x;
        long a_y = A * b_y / 100;
        System.out.println(a_x + a_y);
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        final long A = sc.nextLong();
        String B = sc.next();
        int b_x = Integer.valueOf(B.substring(0, 1)), b_y = Integer.parseInt(B.substring(2));
        long a_x = A * b_x;
        long a_y = A * b_y / 100;
        System.out.println(a_x + a_y);
    } main {
        Scanner sc = new Scanner(System.in);
        final long A = sc.nextLong();
        String B = sc.next();
        int b_x = Integer.valueOf(B.substring(0, 1)), b_y = Integer.parseInt(B.substring(2));
        long a_x = A * b_x;
        long a_y = A * b_y / 100;
        System.out.println(a_x + a_y);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) final long A = sc.nextLong(); A sc.nextLong() sc.nextLong sc String B = sc.next(); B sc.next() sc.next sc int b_x = Integer.valueOf(B.substring(0, 1)) b_x Integer.valueOf(B.substring(0, 1)) Integer.valueOf Integer B.substring(0, 1) B.substring B 0 1 b_y = Integer.parseInt(B.substring(2)); b_y Integer.parseInt(B.substring(2)) Integer.parseInt Integer B.substring(2) B.substring B 2 long a_x = A * b_x; a_x A * b_x A b_x long a_y = A * b_y / 100; a_y A * b_y / 100 A * b_y A b_y 100 System.out.println(a_x + a_y) System.out.println System.out System System.out a_x + a_y a_x a_y String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        final long A = sc.nextLong();
        String B = sc.next();
        int b_x = Integer.valueOf(B.substring(0, 1)), b_y = Integer.parseInt(B.substring(2));
        long a_x = A * b_x;
        long a_y = A * b_y / 100;
        System.out.println(a_x + a_y);
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        final long A = sc.nextLong();
        String B = sc.next();
        int b_x = Integer.valueOf(B.substring(0, 1)), b_y = Integer.parseInt(B.substring(2));
        long a_x = A * b_x;
        long a_y = A * b_y / 100;
        System.out.println(a_x + a_y);
    }
} Main

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        final long A = sc.nextLong();
        String B = sc.next();
        int b_x = Integer.valueOf(B.substring(0, 1)), b_y = Integer.parseInt(B.substring(2));
        long a_x = A * b_x;
        long a_y = A * b_y / 100;
        System.out.println(a_x + a_y);
    }
}
