How about the part in which distribution is according to individual contribution? You work more, you get more. You do nothing, you get nothing.
I've never heard of that socialism.
"There are many varieties of socialism and there is no single definition encapsulating all of them"
"In the Marxist theory of historical materialism, it is predicted that further advances in technology and the productive forces will give rise to a more advanced stage of development referred to as communism, a society in which classes and the state are no longer present, and there is access abundance to final goods, and thus distribution is based on to each according to his need."
to each, according to his need. Not predicated on input.