input: Write a python function to compute the nth Fibonacci number using recursion.
  assert fibonacci(10) == 34
  assert fibonacci(1) == 0
  assert fibonacci(2) == 1
  assert fibonacci(5) == 3
output: def fibonacci(n):
      if n == 1:
          return 0
      elif n == 2:
          return 1
      else:
          return fibonacci(n - 1) + fibonacci(n - 2)