Attempt Number: 3
Error Message: Action not unique compared to other actions chosen from this state before. Choose a new action

Action Reasoning:
The next action in the plan is to board passenger p4 onto fast1 at floor n2. This action moves us closer to the goal state by preparing p4 for transport to their destination.

New State Description:
- fast0: At floor n0, 0/2 passengers.- fast1: At floor n2, 2/2 passengers (p5 and p4 on board).- slow0-0: At floor n2, 0/1 passengers.- p0: On floor n2.- p1: On floor n1.- p2: On floor n5.- p3: On floor n5.- p4: On board fast1.- p5: On board fast1.- p6: On floor n2.

Action Chosen:
(board p4 fast1 n2 n1 n2)
