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:  4 3 5 3 0 0 0 0 0 0 0 0 0 0 0 0 0 3 1 2 5 2 7 7
Output: 7 4 3 5 3 0 0 0 0 0 0 0 0 0 0 0 0 0 3 1 2 5 2 7

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

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

Below is a test input grid. Predict the corresponding output grid by applying the rule you found.
Input:
0 8 4 8 1 2 5 9 0 0 0 0 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