Hi! I need a regexp that does the following:

For example we're having a string "abcmnbcxyz" 

 I need to build a regexp that will find everythig that goes before "z" but not containing "bc"

I was trying to use lookups like that one: "(?<!bc).*?z" but it matches whole string. positive lookbehind ("(?<=bc).*?z") matches "mnbcxyz"

And I need regexp to match "xyz".

Any suggestions?