In this task, you will be presented with a question in Persian. Based on the knowledge you need to answer the question, classify the question into "math_and_logic", "literature", or "common_knowledge".

Let me give you an example: عدد 30 را بر نیم تقسیم می کنیم و سپس عدد 10 را به آن اضافه می کنیم. نتیجه کدام گزینه است؟
The answer to this example can be: math_and_logic
Here is why: This is a good example. You need mathematical knowledge to answer this question.

OK. solve this:
کدام رود از ارتفاع چهل چشمه سرچشمه می گیرد؟
Answer:
common_knowledge