import java.util.*;
import java.lang.*;
public class F {
    public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int apple = sc.nextInt();
    int piece_apple = sc.nextInt();
    int applePie;
    applePie = (apple * 3 + piece_apple)/2;
        System.out.println(applePie);













    }
}

