There are 2 shapes on a 5x5 grid. Which shape is closest to the red square in terms of Manhattan distance? The final answer is the grid position of the closest shape like (row_index, column_index).
<think>Target shape: red square at (1, 3)
Distance from target shape to pink right_triangle at (3, 1): 4
Closest shape is the pink right_triangle at (3, 1) with distance 4</think>

<answer>(3, 1)</answer>