import java.util.*;



public class Main_yukicoder3017 {

    public static void main(String[] args) {
    	Scanner sc = new Scanner(System.in);

    	long s = sc.nextInt();
    	long k = sc.nextInt();

    	System.out.printf("%d.%02d\n", s * k / 100, s * k % 100);


    	sc.close();
    }
}