turtle polygon as specified by user input

[johneven]

The following is an exercise question from tutorial course and my code.

Write a program that asks the user for the number of sides, the length of the side, the color, and the fill color of a regular polygon. The program should draw the polygon and then fill it in.

import turtle      
wn = turtle.Screen()  
alex = turtle.Turtle()

sides = input ("Number of sides in polygon?"  )
length = input ("Length of the sides in polygon?" )
colorname = input ("Color of polygon?" )
fcolor = input ("Fill color of polygon?")

alex.color = (colorname)
alex.fillcolor = (fcolor)

for i in range(sides):
   alex.forward (length)
   alex.left (360 / sides)

Input pop-ups work, but otherwise, no output.