input: Write a function to generate the nth Fibonacci number using a recursive approach. If the input is 1 or 2, return 1. For other values of n, return the sum of the two preceding Fibonacci numbers. If the input is less than 1, return 0.
  def fibonacci(n):
      if n < 1:
          return 0
      elif n == 1 or n == 2:
          return 1
      else:
          return fibonacci(n - 1) + fibonacci(n - 2)
  
  assert fibonacci(1) == 1
  assert fibonacci(2) == 1
  assert fibonacci(10) == 55
  assert fibonacci(0) == 0
  assert fibonacci(-1) == 0
output: def fibonacci(n):
      if n < 1:
          return 0
      elif n == 1 or n == 2:
          return 1
      else:
          return fibonacci(n - 1) + fibonacci(n - 2)