Current State ID: 24
Current State Description: Block 'a' is on the table and clear. Block 'c' is on top of block 'b' and supporting block 'd'. Block 'b' is on the table. Block 'd' is on top of block 'c' and clear. The hand is empty.

Child State ID: 31
Action Taken: pick-up(a)
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'.

Child State ID: 33
Action Taken: unstack(d, c)
State Description: Block 'a' is on the table and clear. Block 'c' is on top of block 'b' and clear. Block 'b' is on the table. Block 'd' is held in the hand. The hand is not empty.

