Your task is to extract order size from the given text that is description of a trading Strategy if there is any order size mentioned.

Order size is of type OrderSize which is an abstract class with 3 subclasses:
- USD(value: float)
- Contracts(value: float)
- PercentOfEquity(value: float)

value: is a float value that represents the order size in USD, number of contracts or percentage of equity respectively. If there is X percent of equity, the value should be X.

Order size can also be `None` if there is no order size mentioned in the text.

[RESPONSE INSTRUCTIONS]
- Your task is to extract the order size from the given text and return it in the format: order_size=OrderSizeType(value), where OrderSizeType is one of the subclasses (USD, Contracts, PercentOfEquity) and value is the extracted value.
- If no order size is mentioned in the text, return `None`
- Do NOT include any additional text or explanations

Here is the description of the strategy you need to extract the order size from:
[DESCRIPTION]
{description}