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

public class Main
{
	public static void main (String[] args)
	{
	Scanner sc = new Scanner(System.in);
	int a = sc.nextInt();
	int p = sc.nextInt();
	int x = 3*a + p;
	System.out.println(x/2);
	}
}
