import java.util.Scanner;
public class Main {
 
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
 
		int  A = sc.nextInt();
		int  P = sc.nextInt();
		
		int D = (3 * A + P) / 2;
			System.out.println(D);
		
	}
} 