using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Text;
using System.Text.RegularExpressions;
using System.Linq;

class Magatro
{
    
    static void Main()
    {
        int A, B;
        string[] s = Console.ReadLine().Split(' ');
        A = int.Parse(s[0]);
        B = int.Parse(s[1]);
        Console.WriteLine(function(A, B));
       
    }
    static int function(int a, int b)
    {
        int q = a * 50;
        int w = 8 + 2 * b;
        return q + (q * 10 / w);
    }
}