user: I'm developing an encryption algorithm and it involves creating permutations from the English alphabet. I need to know the number of different ways I can arrange 5 letters from the total 26. Could you calculate that for me?

Available functions:
name: calculate_future_value
description: Calculates the future value of an investment.
parameters: type: dict
properties: present_value: type: float
description: The present value of the investment, in dollars.
interest_rate: type: float
description: The interest rate of the investment, ranging from 0 to 1.
periods: type: integer
description: The number of periods, in years.
required: present_value
interest_rate
periods
name: calculate_permutations
description: Calculates the number of permutations of k elements from a set of n elements.
parameters: type: dict
properties: n: type: integer
description: The number of elements in the set.
k: type: integer
description: The number of elements to choose.
required: n
k
name: get_company_name_by_stock_name
description: Finds the company name of a stock by its stock name.
parameters: type: dict
properties: stock_name: type: string
description: The stock name of the product, in the format of the stock symbol.
required: stock_name