Convert boolean expression to 3 input NOR

Convert boolean expression to 3 input NOR

I was taking a look at this link
http://lizarum.com/assignments/boolean_algebra/chapter3.html to try and
solve an equation I have. The original equation is:
H = MC + MC' + CRD + M'CD'
I simplified it to H = M + CRD + M'CD'
Here is my attempt:
H = ((M + CRD + M'CD')')'
H = ((M)' * (CRD)' * (M'CD')')'
H = (((M)')' + ((CRD)')' + ((M'CD')')'
H = ((M')' + (C'+ R' + D')' + (M + C' + D)')'
Is that final equation a 3 input NOR equation? I have a feeling that I'm
missing a step that makes the first parentheses into three variables.