Parent State ID: 9
State Depth: 5
Action Taken: pick-up(a)
Action Reasoning: To start building the goal stack, we should first pick up block 'a' since it needs to be stacked on block 'c'.
State Description: The hand is holding block 'a'. Block 'a' is no longer on the table and not clear. Blocks b, c, and d remain on the table and clear.
Action Path: ['unstack(c, d)', 'put-down(c)', 'unstack(d, a)', 'put-down(d)', 'pick-up(a)']
