title: Python 3 check negative numbers for input
body: <p>How do you write a Python 3 version of a program that denies negative integer input with a warning and does not allow it to enter ?
  for example,</p>
  
  <pre><code>print (' Hypothenuse ')
  
  print ('______________________________________________')
  
  while True:
      L1=int(input('Value of L1:'))
      L2=int(input('Value of L2:'))
  
      if L1 &gt;= 0:
          if L1 ==0:
              print("L1 Zero")
          else:
              print("L1 Positive Number")
      else:
          print("L1 Negative Number, Please Recheck Input")
  
      if L2 &gt;= 0:
          if L2 ==0:
              print("L2 Zero")
          else:
              print("L2 Positive Number")
      else:
          print("L2 Negative Number, Please Recheck Input")
  
      h= pow(L1,2) + pow(L2,2)
      print('Value of Hypot',h)
  
      print('____________________________________________')
  </code></pre>
  
  <p>My Code executes after the input of L1 and L2 but does not deny the negative input. Help Please?</p>