I was given the following CFG :
$S \rightarrow A\ |\ B$
$A\rightarrow aAa\ |\ abAb\ |\ bAc\ |\ aca\ |\ abcb\ |\ bcc$
$B \rightarrow bBa\ |\ aBb\ |\ babBc\ |\ bca\ |\ acb\ |\ babcc$
And I have to show if it is ambiguous by giving two leftmost derivations for the same word.
I am pretty sure that there are two leftmost derivations but I can not find them.
I do not need the solution, just a tip where to start with would be enough.