Help with my simple program!

I am playing on Tekkit Main (A Technic Platform modpack) and I am trying to make a program that will keep travelling upwards until the player types "Stop".

This is my code:

print("Please type Stop when you wish to stop:")
Stop = read()
repeat
turtle.up()
until Stop == "Stop"
end

Is anyone able to help me with this?

Greatly Appreciated
-Coocoo99947

this should work:

local function goUp()
  while true do turtle.up() end
end

local function getInput()
  local userInput
  repeat
    userInput = read()
  until userInput == "Stop" -- #or you can have "until userInput:lower() == 'stop'" which would be easier for the user
end

parallel.waitForAny(goUp,getInput)