<!DOCTYPE html>
<html>
<frameset cols="200px,*">
<frame src="https://www.w3schools.com/tags/frame_a.htm">
<frameset rows="*,400">
<frame src="https://www.w3schools.com/tags/frame_b.htm">
<frame src="https://www.w3schools.com/tags/frame_c.htm">
</frameset>
</frameset>