title: Why does my definition for function read a number as if it is negative?
body: <p>I have an issue with my code when defining a function. When giving an input number (defined by n), I want my code to define the Fibonacci series of this number. However, even if the number n is positive, the fibo function still reads the number as it is negative and prints 'None'. Why does it do that? Please find my code below: </p>
  
  <pre><code>def fibo(x):
      if x &gt; 0: 
          if x &lt;= 1:
              return x
          else:
              return(fibo(x-1) + fibo(x-2))
      elif x &lt; 0:
         return None
  
  n = int(input())
  
  for i in range(n):
      print(fibo(i))
  </code></pre>