Suelyn's Counting Sequence

Suelyn counts up from 1 to 9, and then immediately counts down again to 1, and then back up to 9, and so on, alternately counting up and down $$(1, 2, 3,4,5,6,7,8,9,8,7,6,5,4,3,2,1,2,3,4,\ldots ).$$ What is the $ 1000^{\text{th}} $ integer in her list?

  • 1
  • 2
  • 3
  • +
  • 4
  • 5
  • 6
  • -
  • 7
  • 8
  • 9
  • $\frac{a}{b}$
  • .
  • 0
  • =
  • %
  • $a^n$
  • $a^{\circ}$
  • $a_n$
  • $\sqrt{}$
  • $\sqrt[n]{}$
  • $\pi$
  • $\ln{}$
  • $\log$
  • $\theta$
  • $\sin{}$
  • $\cos{}$
  • $\tan{}$
  • $($
  • $)$
  • $[$
  • $]$
  • $\cap$
  • $\cup$
  • $,$
  • $\infty$