Why am I getting a NameError in this script?
===

I'm doing exercises form **[Non-Programmers Tutorial For Python2.6][1]** from [Wikibooks][2].

I have this script:

    #!/usr/bin/env python
    #-*- coding:utf-8 -*-
    
    print("Program to calculate the area of square, rectangle and circle.")
    
    def areaOfSquare():
        side = input("What is the length of one side of the square? ")
        area = side ** 2
        return area
    
    def areaOfRectangle():
        width = input("What is the width of the rectangle? ")
        height = input("What is the height of the rectangle? ")
        area = 2*width+2*height
        return area
    
    def areaOfCircle():
        radius = input("What is the radius of the circle? ")
        area = 3.14 * radius ** 2
        return area
    
    geometry = input("What do you wan to calculate the area of? [S/C/R] ")
    
    str(geometry)
    
    if geometry == "S":
        areaOfSquare()
    elif geometry == "R":
        areaOfRectangle()
    elif geometry == "C":
        areaOfCircle()
    else:
        print "Press S for square, C for circle and R for rectangle."

Here is what happened in shell:

    prompt$ python script.py 
    Program to calculate the area of square, rectangle and circle.
    What do you wan to calculate the area of? [S/C/R] S
    Traceback (most recent call last):
      File "allarea.py", line 22, in <module>
        geometry = input("What do you wan to calculate the area of? [S/C/R]")
      File "<string>", line 1, in <module>
    NameError: name 'S' is not defined

Same thing happens with `C` and `R`.


  [1]: http://en.wikibooks.org/wiki/Non-Programmer%27s_Tutorial_for_Python_2.6
  [2]: http://en.wikibooks.org/wiki/Main_Page