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

public class Magatro
{
    static int A, B;
    static void Main()
    {
        string[] s = Console.ReadLine().Split(' ');
        A = int.Parse(s[0]);
        B = int.Parse(s[1]);
        Console.WriteLine(f(A, B));
    }
   static int f(int N,int K)
    {
        return 50 * N + (int)(((double)50 * N) / (0.8 + 0.2 * K));
    }
}