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

public class Point {
  public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);

    int a = sc.nextInt();
    BigDecimal b = new BigDecimal(sc.next());
    BigDecimal c = new BigDecimal("0.8");
    BigDecimal d = new BigDecimal("0.2");
    BigDecimal e = new BigDecimal(50*a);


    System.out.println(a * 50 + e.divide(c.add(d.multiply(b)), 0, BigDecimal.ROUND_FLOOR).intValue());
  }
}