#pragma warning disable
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System;
class E { static void Main() { new J(); } }
class J
{
	int F() { return int.Parse(Console.ReadLine()); }
	int[] G() { return Console.ReadLine().Split(new char[] { ' ', '\t' }, StringSplitOptions.RemoveEmptyEntries).Select(int.Parse).ToArray(); }
	public J()
	{
		Console.SetOut(new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false });
		var I = G();
		int C = I[0], D = I[1];
		if (5 * C <= 2 * D) Console.WriteLine(7000 * C);
		else if (C > 3 * D) Console.WriteLine(4000 * D);
		else Console.WriteLine((6 * C + 34 * D) * 1000 / 13m);
		Console.Out.Flush();
	}
	long GCD(long a, long b)
	{
		var n = (ulong)Math.Abs(a); var m = (ulong)Math.Abs(b);
		if (n == 0) return (long)m; if (m == 0) return (long)n;
		int zm = 0, zn = 0;
		while ((n & 1) == 0) { n >>= 1; zn++; }
		while ((m & 1) == 0) { m >>= 1; zm++; }
		while (m != n)
		{
			if (m > n) { m -= n; while ((m & 1) == 0) m >>= 1; }
			else { n -= m; while ((n & 1) == 0) n >>= 1; }
		}
		return (long)n << Math.Min(zm, zn);
	}
}