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

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

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

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