input: Write a function to compute the factorial of a given integer and print the result. If the integer is less than or equal to 1, the factorial should return 1.
  assert factorial(7) == 5040
  assert factorial(1) == 1
  assert factorial(0) == 1
  assert factorial(-5) == 1
output: def factorial(n):
      if n <= 1:
          return 1
      result = 1
      for i in range(2, n + 1):
          result *= i
      return result