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

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

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

Below is a test input grid. Predict the corresponding output grid by applying the rule you found.
Input:
8 9 9 4 9 6 0 0 0 0 0 0 0 0 0 0 8 1 3 5 1 3 8 6
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