user: I've just sold some of my photography equipment and ended up with 1000 USD in my pocket. I'm planning a trip to Europe and it would be handy to have euros instead. Could you help me convert this amount into EUR? I'm curious to see how much I'll end up with for my trip. Oh, and just out of interest, I used to love math problems in school – could you calculate the factorial of 1000 for me? I know it's a huge number, but I'm just curious!

Available functions:
name: convert_currency
description: Converts a given amount from one currency to another using the ExchangeRate-API.
parameters: type: dict
properties: amount: type: float
description: The amount of money to convert, in the base currency.
from_currency: type: string
description: The ISO currency code for the base currency.
to_currency: type: string
description: The ISO currency code for the target currency.
required: amount
from_currency
to_currency
name: math_factorial
description: Calculates the factorial of a number.
parameters: type: dict
properties: n: type: integer
description: The number to calculate the factorial of.
required: n