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:  2 9 8 1 5 5 3 0 0 0 0 0 0 0 0 0 0 0 0 8 5 1 9 2 8 1 7
Output: 8 1 7 2 9 8 1 5 5 3 0 0 0 0 0 0 0 0 0 0 0 0 8 5 1 9 2

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

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

Below is a test input grid. Predict the corresponding output grid by applying the rule you found.
Input:
7 8 9 2 3 2 9 4 2 9 8 7 3 9 0 0 0 0 0 0 0 9 6 9 8 2 1
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