37. Team A and Team B cooperate on a large project, planning to work in the order of A, B, A, B, ..., meaning each team works one day and then the other team takes over, so the number of days A and B work is exactly the same; in reality, they worked in the order of A, B, B, A, B, B, ..., and finished two days ahead of schedule, with the last day being A's turn to work. It is known that A's work efficiency is $\frac{2}{3}$ of B's, so the project was actually completed in $\qquad$ days.
$34$