import java.util.*;
import java.util.Scanner;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
public class Main
{
	public static void main (String[] args) throws java.lang.Exception
	{
	    
	    Scanner scanner = new Scanner(System.in);
	    int A = scanner.nextInt();
	    int P = scanner.nextInt();

        int numPiece = 3*A+P;
        int numPie = numPiece / 2;

	    System.out.println(String.valueOf(numPie);
	}
}