1 x = undefined
   2 y = undefined
   3 z = undefined
   4 s = undefined
   5 u = undefined
   6 r = undefined
   7 t = undefined
   8 ReferenceError: "q" is not defined
   9 b = 10
  10 ReferenceError: "b" is not defined
  11 Value of 'a' inside the function 20
  12 Value of 'a' outside the function 10