title: cannot make an input in atom fro python
body: <p>I am new to atom and python in general. 
  I was able to print hello world in atom using python, but I cannot do the program of calculating the circle's area. </p>
  
  <p>Here is what I get. I can do this in IDLE, but I do not know why I cannot input a radius here. Can anyone tell me how to solve it? Thank you! </p>
  
  <p>(I have already saved the file)
  <img src="https://i.stack.imgur.com/089ZN.png" alt="1"></p>