A few Czech surnames do not differ for men and women in the nominative case (the case used for the subject of a sentence). Those include surnames whose male form is genitive plural, (e.g. "Jirků", "Janků") and those whose male form is an adjective with the suffix "-í" (e.g. "Tachecí", "Jarní"). Note that these are only identical in two of the seven grammatical cases; in the other five, the male and female forms differ, as per the soft adjective declension. The woman's surname is also not declined if it is of foreign origin and adding the suffix "-ová" would be awkward or unfeasible: Olga Walló, Blanka Matragi.