Categorize the following countries according to continent: Spain, Mexico, China, Japan.
Spain, Mexico, China, Japan
Here are the countries categorized according to their respective continents:

Europe: Spain

North America: Mexico

Asia: China, Japan.
Complete the following task based on the instruction and optional input provided.### Instruction:
Categorize the following countries according to continent: Spain, Mexico, China, Japan.

### Input:
Spain, Mexico, China, Japan

### Output:
Here are the countries categorized according to their respective continents:

Europe: Spain

North America: Mexico

Asia: China, Japan.