using System;

class Score
{

	static public void Main(string[] args)
	{
		int A, B;
		string[] s;
		s = Console.ReadLine().Split(' ');
		A = int.Parse(s[0]);
		B = int.Parse(s[1]);

		Console.WriteLine(50*A + (int)(50*A / (0.8 + 0.2 * B)));
	}

}