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

Action Reasoning:
To progress towards the goal state, we need to move fast1 to floor n4, where p3 is waiting. This allows us to board p3, aligning with the next step in the valid plan.

New State Description:
- fast0: At floor n0, 0/2 passengers.- fast1: At floor n4, 1/2 passengers (p2 on board).- slow0-0: At floor n2, 0/1 passengers.- p0: On floor n4.- p1: On floor n1.- p2: On board fast1.- p3: On floor n4.- p4: On floor n2.- p5: On floor n5.- p6: On floor n2.

Action Chosen:
(move-up-fast fast1 n3 n4)
