my ($match) = $body =~ /(?<=a)([^c]*c[^c]*c[^c]*)(?=c)/;

##</code><code>##

my ($match) = $body =~ /(?<=a)([^c]*(?:c[^c]*){2})(?=c)/;

##</code><code>##

my ($match) = $body =~ /(?<=a)([^ac]*(?:c[^ac]*){2})(?=c)/;