using System;
using System.Linq;

namespace contest154
{
    class Program
    {
        static void Main(string[] args)
        {
            var AB = Console.ReadLine().Split(' ')
                .Select(a => int.Parse(a)).ToArray();
            var A = AB[0];
            var B = AB[1];

            var result = 50 * A + Math.Floor((50 * A) / (0.8 + 0.2 * B));
            Console.Write(result);
        }
    }
}