using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Score
{
	class Program
	{
		static void Main()
		{
			var InputData = Console.ReadLine().Split(' ').Select(value => Convert.ToInt32(value)).ToList();

			Console.WriteLine((50 * InputData[0]) + (250 * InputData[0]) / (4 + InputData[1]));
		}
	}
}