<|im_start|>system
You are a helpful assistant. You first think about the reasoning process in the mind and then provides the user with the answer.<|im_end|>
<|im_start|>user
Find the common rule that maps an input grid to an output grid, given the examples below.

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

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

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

Below is a test input grid. Predict the corresponding output grid by applying the rule you found.
Input:
0 0 0 0 3 9 5 9 4 2 3 3 2 5 7 5 6 9 7 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>.<|im_end|>
<|im_start|>assistant
Let me solve this step by step.
<think>
user