文章中的页眉和页脚问题

Question

我想在 RO 和 LE 位置获取页眉；仅在 LE 获取页脚，但在我的代码中它不起作用。

梅威瑟：

\documentclass[12pt,a4paper]{article}
\usepackage{amssymb,amsmath}
\usepackage{enumerate}
\usepackage{multicol}
\usepackage{fancybox}% ovalshape boxed text
\usepackage{fancyhdr}

\pagestyle{fancy}
\fancyhf{}
\chead{(\thepage)}

\fancyhead[RO,LE]{\itshape  \ovalbox{M(2nd Sem)- Mathematics-H-CC-3/CBCS}}
\fancyfoot[RO]{Please Turn Over}

\renewcommand{\headrulewidth}{0pt}
\renewcommand{\footrulewidth}{0pt}

\newlength{\finalwidth}
\newlength{\tempwidthA}
\newlength{\tempwidthB}
\makeatletter
\AtEndDocument{\write\@auxout{\global\finalwidth=\the\tempwidthB}}
\makeatother
\newcommand{\marksA}[1]{% the Bourbaki trick
    \settowidth{\tempwidthA}{\quad#1}%
    \ifdim\tempwidthA>\tempwidthB \global\tempwidthB=\tempwidthA\fi
    \unskip
    {\nobreak\hfill\penalty50\hskip1em\null\nobreak
        \hfill \makebox[0pt][l]{\makebox[\finalwidth][r]{\normalfont\quad#1}}%
        \parfillskip=0pt \finalhyphendemerits=0 \par}%
}

\begin{document}
    \thispagestyle{empty}
%   \pagenumbering{roman}

    \begin{flushright}
\itshape  \ovalbox{M(2nd Sem)- Mathematics-H-CC-3/CBCS}
    \end{flushright}
    \bigskip
    \begin{center}
        \textbf{\Large 2019}\\[2ex]
        \textbf{MATHEMATICS -- HONOURS}\\
        \textbf{Paper:CC-3}\\
        \textbf{(Module-I)}\\
        \textbf{Full Marks: 65}\\[2ex]
        {\itshape The figures in the margin indicate full marks.}\\
        {\itshape Candidates are requested to give their answer in their
            own words as far as practicable}\\
            $\mathbb{R,Q,N}$  denotes respectively the set of all real numbers, the set of all rational numbers and the set of all natural numbers
    \end{center}

    % FRONT Matter

    \pagenumbering{arabic}


\begin{enumerate}

    \item Answer the following multiple choice questions. Choose the option with justification.\marksA{$2\times 10$}

    \begin{enumerate}
        \item The supreme of the complement $A$ in $\mathbb{R}$, where $A=\{x\in \mathbb{R}: x^2-3x-2\geq 0\},$

        \begin{multicols}{2}
            \begin{enumerate}[(i)]
                \item $\{x^2:x\in [0,1]\}$
                \item $\{ 5+\sqrt{7}t:t\in \mathbb{Q} \}$
                \item $(0,1])\cap (\mathbb{R}\setminus \mathbb{Q})$
                \item $\{\frac{1}{x}:x\in(0,\infty) \}$
            \end{enumerate}
        \end{multicols}     

        \item sub item
        \begin{enumerate}[(i)]
            \item sub of sub item
            \item sub of sub item
        \end{enumerate}

        \item item 
    \end{enumerate}


\end{enumerate}
\newpage
Sample

\newpage
Sample  

\newpage
Sample

\newpage
Sample

\end{document}