c#
using System;
using System.Threading.Tasks;
using static System.Console;
using static System.Math;

class program{
  static void Main(string[] args){
    program p= new program();
      p.Run();
  }
  void Run(){
    int[] ap=Readint();
    int p=ap[0]*3+ap[1];
    p=(int)(p/2);
    WriteLine(p.ToString());
  }
  int[] Readint(){
    string[] inp= ReadLine().Split();
    int n=inp.Length;
    int[] res=new int[n];
    for(int i=0;i<n;i++){
      res[i]=int.Parse(inp[i]);
    }
    return res;
  }
}