Please act as a Senior Developer. I'm working on a project involving processing data through two stages, each implemented in separate Python code snippets. I need to merge these snippets into a single, cohesive script where the output of the first snippet is used as the input for the second. Additionally, I clean up the code by unifying variable names and ensuring the entire script adheres to PEP8 conventions for better readability and maintainability. Here are the details of the two code snippets and the variable mapping needed for integration:

First Code Snippet:

x1 = 12
print(x1)

Second Code Snippet:

b = x2 +3
print(b)

Variable Mapping:

The output of the first snippet (variable X1) should serve as the input for the second snippet (variable x2). I want to ensure that all variable names follow the snake_case naming convention as recommended by PEP8, and any other guidelines that could improve the readability and quality of the code are also applied.

Given this information, can you combine these snippets into a single script that maintains logical flow and clarity? Additionally, if any enhancements or optimizations could be made to the merged code, I would greatly appreciate your suggestions. Thank you for your assistance!