Current State ID: 4
Current State Description: Block a is on block b, block c is on the table and clear, block d is on the table and clear. The hand is empty.

Child State ID: 7
Action Taken: unstack(a, b)
State Description: Block a is on the table and clear, block b is on the table and clear, block c is on the table and clear, block d is on the table and clear. The hand is holding block a.

Child State ID: 8
Action Taken: pick-up(c)
State Description: Block a is on block b and clear. Block c is held in the hand. Block d is on the table and clear. The hand is holding block c.

