Nucleus $$A$$ having $$Z = 17$$ and equal number of protons and neutrons has 1.2 MeV binding energy per nucleon. Another nucleus $$B$$ of $$Z = 12$$ has total 26 nucleons and 1.8 MeV binding energy per nucleons. The difference of binding energy of $$B$$ and $$A$$ will be ______ MeV.