I've compiled a list of Marie's safe strings. Please feel free to add on if I missed anything. Some of these are just string variations.
:6::P::P: -5
:P::P::6::P::P: -5
:6::P::K: -6
:P::P::6::P::K: -6
:P::P::P: -5
:9::P: -5
:p+k: -4 (B!)
:1::P: :p+k: -4 (B!)
:1::P::P: -4
:6::p+k: -4
:3::P::K...