title: How to make input only accept a-z etc
body: <p>I'm having trouble getting my input to accept only a-z and A-Z letters. This is what I came up with</p>
  
  <pre><code>        while(not(studentName == "END")):
      studentName = input("What is the name of the student (END to finish) ")
      if not re.match("^[a-z]*$", studentName):
          print("Only letters are allowed")
      elif len(studentName) == 0:
          print("Insufficient characters. Please try again.")
      else:
          studentsNames.append(studentname)
  </code></pre>
  
  <p>However I just come up with an error "re not defined".
  What do I do :C</p>