I’m trying to show that L6={cnambp:n+m=p,p?6} is not regular. I need a little help, I was…

I’m trying to show that
L6={cnambp:n+m=p,p?6}
is not regular. I need a little help, I was practicing the pumping
lemma, and I encountered this language, I saw these conditions and
got totally confused, what to do now?
Earlier I showed that
L5={anbn:n?0}
is not regular. In this Language it was very simple to choose
w, namely
w=apbp, where
p is the pumping length. But this new Language is
complicated, so I thought you guys could help me out.