A conversation between User and Assistant. The user asks a question, and the Assistant solves it. The assistant first thinks about the reasoning process in the mind and then provides the user with the answer.
User: Find the common rule that maps an input grid to an output grid, given the examples below.

Example 1:
Input:  3 2 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 8 9 8 7 1
Output: 8 7 1 3 2 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 8 9

Example 2:
Input:  6 3 7 9 8 4 5 2 8 1 5 7 6 3 7 4 2 1 1 5 9 9 5 8
Output: 9 5 8 6 3 7 9 8 4 5 2 8 1 5 7 6 3 7 4 2 1 1 5 9

Example 3:
Input:  1 3 6 5 0 0 0 0 7 3 9 5 5 6 3 2 6 4 7 7 8 2 8 7
Output: 2 8 7 1 3 6 5 0 0 0 0 7 3 9 5 5 6 3 2 6 4 7 7 8

Below is a test input grid. Predict the corresponding output grid by applying the rule you found.
Input:
0 0 0 0 5 9 9 9 4 9 4 6 0 0 0 0 0 0 0 0 0 0 0 0
Show your work in <think> </think> tags, and return the answer in <answer> </answer> tags with space between each number. For example <answer> 1 3 5 7 </answer>.
Assistant: Let me solve this step by step.
<think>
user