Current State ID: 0
Current State Description: In the initial state, block c is on the table. Block b is on top of block c and is clear, meaning there is no block on top of it. Block a is on the table and is clear. Block d is on the table and is clear. The hand is empty.

Child State ID: 1
Action Taken: pick-up(blockD)
State Description: Block A is on the table and clear. Block B is on block C and clear. Block C is on the table and supports block B. Block D is held in the hand and is no longer on the table. The hand is holding block D.

Child State ID: 3
Action Taken: unstack(block_b, block_c)
State Description: Block A is on the table and clear. Block B is in the hand and no longer clear. Block C is on the table and now clear. Block D is on the table and clear. The hand is holding block B.

