using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;



 class Program
{


	public static void Main()
	{
		
		long[] triangle = Console.ReadLine().Split(' ').Select(long.Parse).ToArray();
            long triX = triangle[1];
            Console.Write((triX*3)+((triX/2)*3)+(triX+(triX/2)));
	}
}	
	
	
	