title: Use variable in randint argument
body: <p>Total beginner here,</p>
  
  <p>I'm writing a program that rolls dice for the user, and I want it to be able to change the number of faces of the die per user input. I can't seem to get the variable     amount_faces     to work as an     int    for the     randint()    function, I get a "TypeError: cannot concatenate 'str' and 'int' objetcts" error everytime:</p>
  
  <pre><code>from sys import exit
  from random import randint
  
  def start():
      print "Would you like to roll a dice?"
      choice = raw_input("&gt;")
      if "yes" in choice:
          roll()
      elif "no" in choice:
          exit()
      else:
          print "I can't understand that, try again."
          start()
  
  def roll():
      print "How many faces does the die have?"
      amount_faces = raw_input("&gt;")
      if amount_faces is int:
          print "The number of faces has to be an integer, try again."
          roll()
      else:            
          print "Rolling die...."
          int(amount_faces)
          face = randint(1,*amount_faces)
          print "You have rolled %s" % face
          exit()
  
  start()
  </code></pre>
  
  <p>Any clues?</p>