More efficient way for Cyrillic masks

[Toetje]

For example the combination d1b0 (it should only do d0b0) is not in the Cyrillic alphabet, but with this mask it will try this combination, even though I don't really want to try it.

[edit]
Perhaps to clarify a bit more, the lowercase charset should only do:
d0b0 d0b1 d0b2 d0b3 d0b4 d0b5 d191 d0b6 d0b7 d0b8 d0b9 d0ba d0bb d0bc d0bd
d0be d0bf d180 d181 d182 d183 d184 d185 d186 d187 d188 d189 d18a d18 bd18c
d18d d18e d18f