CC Error

function next()
 turtle.turnRight()
 turtle.forward()
 turtle.turnLeft()
end
function mine()
 turtle.dig()
 next()
 turtle.dig()
 next()
 turtle.dig()
 turtle.turnLeft()
 turtle.forward()
 turtle.forward()
 turtle.turnRight()
end
function place()
 turtle.select(2)
 turtle.place()
 next()
 turtle.place()
 next()
 turtle.place()
 turtle.turnLeft()
 turtle.forward()
 turtle.forward()
 turtle.turnRight()
 turtle.select(1)
end
function button()
 rs.setOutput("top", true)
 sleep(0.5)
 rs.setOutput("top", false)
 sleep(1.75)
 rs.setOutput("top", true)
 sleep(0.5)
 rs.setOutput("top", false)
end
print("How much obsidian would you like?")
input = read()
amount = input/3
if turtle.getItemCount(2) >= input then
 for i=1,amount do
  place()
  button()
  mine()
 end
else
 print("Not enough redstone!")
end
print("Mining is complete!")