input: Write a function to generate a Fibonacci sequence of the first n numbers. The function should return the nth Fibonacci number where the sequence is defined as F(1) = 0, F(2) = 1, and F(n) = F(n-1) + F(n-2) for n > 2.
  
  def Fibonacci(n):
      if n==1:
          return 0
      elif n==2:
          return 1
      else:
          return Fibonacci(n-1)+Fibonacci(n-2)
  
  assert Fibonacci(1)==0
  assert Fibonacci(2)==1
  assert Fibonacci(3)==1
  assert Fibonacci(4)==2
  assert Fibonacci(5)==3
  assert Fibonacci(6)==5
  assert Fibonacci(7)==8
  assert Fibonacci(8)==13
output: def Fibonacci(n):
      if n == 1:
          return 0
      elif n == 2:
          return 1
      else:
          return Fibonacci(n-1) + Fibonacci(n-2)