```
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{makeidx}
\usepackage{graphicx}

\begin{document}

        \[
        P=\left[
        \begin{array}{cccc|cccccccccccc}
        1      & 1 & \dots    &1            & 1 & 1&  \dots       & 1 \\
        1      &   &                      &                       &   &             &   \\
        \vdots &   &        \textbf{\Huge{C}}               & &&&  \textbf{\Huge{0}}  &    \\
        1      &   &                      &                       &   &             &   \\
        \cline{2-8}
        1      &   &                      &                       &   &             &   \\
        \cdots &   &     \textbf{\Huge{0}}     &                       &   &&\textbf{\Huge{D}} \\
        1      &   &                      &                       &   &             &
        \end{array}
        \right]
        \]

\end{document}

```

I have written the following code. The problem I am facing is I want the line to appear after the first row.
Please find the picture attached of the matrix I want to have.
How do I remove the line from the first row?
Please help

[![enter image description here](https://i.stack.imgur.com/5B9IU.jpg)](https://i.stack.imgur.com/5B9IU.jpg)

I would be happy and grateful if it be done by just doing some manipulations to my given code.
I want to do it without using any packages