Attempt Number: 4
Error Message: The action and resulting child state have already been explored.

Action Reasoning:
The last action taken was "paint-up", where robot1 painted tile_0-0 black. According to the rules, after a "paint-up" action, the robot should move horizontally if there are unpainted tiles in the row above it. Since tile_0-1 is not yet painted and is directly above tile_1-0, the next best action is to move robot1 to the right, from tile_1-0 to tile_1-1. This move will position the robot correctly to change its paint color and paint tile_0-1 in the subsequent actions.

New State Description:
Robot1 has moved from tile_1-0 to tile_1-1. Tile_1-0 is now clear, and tile_1-1 is occupied by robot1, which is still holding the black paint.

Action Chosen:
right(robot1, tile_1-0, tile_1-1)
