input: Write a function to calculate the nth Fibonacci number. If the input is less than 0, print "Incorrect input". If the input is 0 or 1, return the input value. For any other value of n, return the sum of the (n-1)th and (n-2)th Fibonacci numbers. Function header: def Fibonacci(n):
  assert Fibonacci(0)==0
  assert Fibonacci(1)==1
  assert Fibonacci(5)==5
  assert Fibonacci(10)==55
output: def Fibonacci(n):
      if n < 0:
          print("Incorrect input")
      elif n == 0:
          return 0
      elif n == 1:
          return 1
      else:
          return Fibonacci(n-1) + Fibonacci(n-2)