package m.shin;
import java.math.BigDecimal;
import java.util.Scanner;
public class Con445 {

	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
		BigDecimal a = new BigDecimal(s.next()) , b = new BigDecimal(s.next());
		s.close();

		b = b.multiply(new BigDecimal("0.2")).add(new BigDecimal("0.8"));
		BigDecimal c = a.multiply(new BigDecimal("50")).divide(b, BigDecimal.ROUND_DOWN);
		a = a.multiply(new BigDecimal("50")).add(c);
		System.out.println(a.toString());
	}

}