The text in my fancyhead is written in small caps. I would like to have it not in small caps. How can I do?

This is my fancyhead:

```
\usepackage{fancyhdr}
\lhead[\rm\thepage]{\fancyplain{}{\sl{\rightmark}}}
\rhead[\fancyplain{}{\sl{\leftmark}}]{\rm\thepage}
\chead{}\lfoot{}\rfoot{}\cfoot{}
\pagestyle{fancy}

```

something like that:

![enter image description here](https://i.stack.imgur.com/yuIvL.png)