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

namespace agc030_a
{
    class Program
    {
        static void Main(string[] args)
        {
            var text = Console.ReadLine();
            var list = text.Split(' ').ToList().Select(x => int.Parse(x)).ToList();

            var a = list[0];
            var b = list[1];

            var c = a * 3 + b;

            Console.WriteLine((int)(c / 2);
        }
    }
}
