import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		Scanner sc = new Scanner(System.in);
 
		int A = sc.nextInt();
		int P = sc.nextInt();
		int B;
 
		System.out.println((A*3 + P)/2);
	}
}