If we want to call somebody by name, we should always add a special suffix “san”. It follows the given name or surname of the person being addressed, regardless of age or gender: “Nastya-san”, “Dima-san”, “Putin-san”, etc. It’s possible to omit “san” only if we are talking to a very close friend or a family member. In this case we may use a given name (“Nastya”) or add a diminutive suffix. It will be “chan” for a girl – “Alya-chan”; and “kun” for a boy “Dima-kun”.