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