import java.util.*;

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