input: Write a function to generate the nth Fibonacci number using a recursive approach. The function should return the nth number in the Fibonacci sequence. If n is 1 or 2, the function should return 1. For other values of n, the function should return the sum of the two preceding numbers in the sequence. If n is 0 or negative, the function should return 0.
  
  def fibonacci(n):
      if n <= 0:
          return 0
      elif n == 1 or n == 2:
          return 1
      else:
          return fibonacci(n - 1) + fibonacci(n - 2)
  
  assert fibonacci(10)==55
  assert fibonacci(1)==1
  assert fibonacci(2)==1
  assert fibonacci(5)==5
  assert fibonacci(0)==0
  assert fibonacci(-3)==0
output: def fibonacci(n):
      if n <= 0:
          return 0
      elif n == 1 or n == 2:
          return 1
      else:
          return fibonacci(n - 1) + fibonacci(n - 2)