title: Bad operand type for unary-:"str'
body: <p>New to Python and can't figure out what's wrong with the code below. </p>
  
  <pre><code>a = input('input a number: ')
  if int(a) &gt;=0:
      print(a)
  else:
      print(-a)
  </code></pre>
  
  <p>When enter -2, the output should be 2.</p>
  
  <p>However, I got a error code:</p>
  
  <pre><code>TypeError: bad operand type for unary-:"str' on print(-a)
  </code></pre>
  
  <p>Can anyone help? Thanks.</p>