upuparrows - undefined control sequence

Question

So, I have a great trouble. When you define a vector for a first time to someone you use the term that two pointed segments are parralel and have the same orientation. So, for that you use in latex upuparrows. But when I try this $AB \upuparrows CD$ it cracs and informs me on some undefined control sequence. This is my first time to work with upuparrows command, so I don't know anything. Please help it's urgent.

Answer 1

Something like this?

\documentclass{article}
\usepackage{amssymb}
\begin{document}
$\upuparrows$
\end{document}