how to add ‘random’ text link to header?

I just want the word ‘RANDOM’ in my header as a link to a random page
Currently I have managed to add p’revious’ and ‘next’ in the header:

‘<?php previous_post(‘%’, ‘PREVIOUS ‘, ‘no’); ?>
<?php next_post(‘%’,’ NEXT’, ‘no’); ?> ”

I’ve checked and this seems to be on the right track but I can’t complete it:
?php
$randomnumber = rand(1,3);
?
Any help?Thanks,
Patrick.