def calculate_factorial(num):
    factorial = 1
    if num < 0:
        print("Factorial does not exist for negative numbers.")
    else:
        for i in range(1, num + 1):
            factorial *= i
        print(f"The factorial of {num} is {factorial}")

# Example usage:
number = int(input("Enter a number to calculate factorial: "))
calculate_factorial(number)