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 x = a*3+p;
		int y = x/2;
		
		System.out.println(y);
	
	}
		
}