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:  6 2 0 0 0 0 0 0 0 3 6 5 7 3 8 8 9 9 1 9 8
Output: 2 0 0 0 0 0 0 0 3 6 5 7 3 8 8 9 9 1 9 8 6

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

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

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