import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int A = sc.nextInt();
        int B = sc.nextInt();
        int c = 50*A;
        double d = c/(0.8+0.2*B);
        int f = c+(int)d;
        System.out.println(f);
    }
}