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 ans = 50 * a + (int)((50 * a) / (0.8 + 0.2 * b));
        System.out.println(ans);
    }
}