input: Write a function to display the first n numbers of a Fibonacci sequence. If n is 1, return 0. If n is 2, return 1. Otherwise, recursively return the sum of the last two numbers in the sequence.
  assert Fibonacci(1)==0
  assert Fibonacci(2)==1
  assert Fibonacci(3)==1
  assert Fibonacci(4)==2
  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)