Parent State ID: 24
State Depth: 9
Action Taken: pick-up(a)
Action Reasoning: To achieve the goal state, we need to move block 'a' on top of block 'b'. Since block 'a' is already clear and on the table, the next step is to pick it up.
State Description: Block 'a' is held in the hand. Block 'c' is on top of block 'b' and supporting block 'd'. Block 'b' is on the table and clear. Block 'd' is on top of block 'c' and clear. The hand is holding block 'a'.
Action Path: ['unstack(d, a)', 'put-down(d)', 'unstack(a, c)', 'put-down(a)', 'pick-up(d)', 'stack(d, c)', 'unstack(d, c)', 'stack(d, c)', 'pick-up(a)']
