Mr. Pinter's abstract algebra book on page-81 states that:

"If $\displaystyle \pi \in S_n$, then $\displaystyle \pi$ cannot be both an odd permutation and an even permutation."

--where $\displaystyle S_n$ is a symmetric group.

There's a website that tells:

PlanetMath

$\displaystyle \pi=\left( \begin{array}{ccccccc} 1 & 2 & \cdots & m-r+1 & m-r+2 & \cdots & m \\ r & r+1 & \cdots & m & 1 & \cdots & r-1 \end{array} \right)$

But I can't figure out what will be $\displaystyle r$ here?