Mathematics is the foundation. I can't say exactly how long it will take. See how much time you arrange to see and do math every day.

Mathematics review should make a review plan according to your own situation, and how much to read every day. If you have a good foundation, you will spend less time every day. If you don't, you will spend more time.

There is no need to review politics in summer vacation. You can watch more for 4 to 5 hours every day. In September, it will take up to 3 hours a day, and then 1 to 2 hours a day.

So you should spend more time laying a good foundation in the summer vacation.

Review of advanced mathematics, modernity and probability. You regard them as a whole and review them in order. According to my personal experience, advanced mathematics takes more time, mainly because there are more contents, so much time for line generation and probability review.

You'd better make a plan first, what you will do and see in mathematics in the past six months, and then proceed according to the plan.

I wish you success in your postgraduate entrance examination