input: Write a function to calculate the Fibonacci numbers up to a given number. If the given number is 0 or 1, return the number itself. If the given number is greater than 1, recursively calculate the sum of the previous two Fibonacci numbers.
  
  def Fibonacci(n): 
      if n == 0: 
          return 0
      if n == 1: 
          return 1
      else: 
          return Fibonacci(n-1) + Fibonacci(n-2)
  
  assert Fibonacci(0) == 0
  assert Fibonacci(1) == 1
  assert Fibonacci(5) == 5
  assert Fibonacci(10) == 55
  assert Fibonacci(15) == 610
output: def Fibonacci(n): 
      if n == 0: 
          return 0
      if n == 1: 
          return 1
      else: 
          return Fibonacci(n-1) + Fibonacci(n-2)