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:  8 7 8 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 4 7
Output: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 4 7 8 7 8 5

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

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

Below is a test input grid. Predict the corresponding output grid by applying the rule you found.
Input:
7 8 3 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9 7
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