title: Can't assign to literal python error
body: <p>I need to make a program that prompts the user for points received on a "quiz" (0-5). Then give them a grade back based on the scale of 5 = A, 4 = B, 3 = C, etc. When I try to assign the grades to the numbers, it says <code>Cannot assign to literal</code>.</p>
  
  <pre><code>grade = eval(input("How many points did you receive? "))
  
  grade = str(A, B, C, D, F)
  
  1, 0 = F
  2 = D
  3 = C
  4 = B
  5 = A
  
  
  print("The grade you received was a(n)", str(grade),".")
  </code></pre>