How to change Woocommerce discount calculation formula?

Question

WooCommerce

The bottom line is this:
The supplier gives unloading.
There is a price in the unloading, let's say 1000 rubles.
There is also a discount on download. If there is no discount, then the field in the upload is not empty, there is 0.
Therefore, all products in the catalog start to cost 0 rubles.
How to change Woocommerce discount calculation formula?
To be X (price) - discount = Discounted price.
And not just a variable substitution.