using System;
using System.Collections.Generic;
using System.Collections;
using System.Linq;
using System.Numerics;




namespace contest
{

    class contest
    {


        static void Main(string[] args)
        {


            //int n = int.Parse(Console.ReadLine());
            //var input = Console.ReadLine().Split().Select(int.Parse).ToArray();

            //var num = Console.ReadLine().Split().Select(int.Parse).ToArray();



            
            var num = Console.ReadLine().Split().Select(int.Parse).ToArray();
            int a = num[0];
            int b = num[1];




            
            Console.WriteLine((double)(50*a+(int)(50*a/(0.8+(0.2*b)))));


           


        }

       

    }


}