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:  2 3 3 6 3 2 1 8 9 7 4 9 5 5 9 4 9 1
Output: 3 3 6 3 2 1 8 9 7 4 9 5 5 9 4 9 1 2

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

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

Below is a test input grid. Predict the corresponding output grid by applying the rule you found.
Input:
2 4 7 3 9 2 3 6 9 0 1 7 7 6 5 1 9 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