UT theoretical chemistry code forum

I would like to calculate chg diff in (PtCo_slab+1 water)-(PtCo_slab)-(1 water). I'm not sure if I can use chgdiff when number of atoms in 2 chgcar are different? Thank you.

I tried to use the script chg2cube.pl but when I have to enter atom types by atomic number I don't know how the program will read. For example, I have Pt 12 atoms Co 12 atom O 1 atom and H 2 atoms. I enter 78 27 8 1 but it have error said NUMBER OF ELEMENT TYPES DOES NOT MATCH NUMBER OF ATOMIC ...