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

Action Reasoning:
The last action taken was moving the robot to the right. According to the logical conclusions, after a move, the next step should be to change the color of the paint gun. Since the robot is currently holding black paint and the next tile in the goal state (tile_0-1) should be painted white, changing the color from black to white is the optimal action.

New State Description:
Robot1, located on tile_1-2, changes its paint gun color from black to white.

Action Chosen:
change-color(robot1, black, white)
