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