using System;

public class Hello
{
    public static void Main()
    {
        string[] line = Console.ReadLine().Trim().Split(' ');
        var a = int.Parse(line[0]);
        var b = int.Parse(line[1]);
        var a50 = a * 50;
        var c = (int)(a50 / (0.8 + 0.2 * b));
        Console.WriteLine(c + a50);
    }
}