Question: In what year did the physicist who founded the Committee on Human Rights in the USSR with Valery Chalidze and Andrei Tverdokhlebov die?
Sentence (from "Andrei Sakharov"): Andrei Dmitrievich Sakharov (Russian: Андре́й Дми́триевич Са́харов ; 21 May 192114 December 1989) was a Russian nuclear physicist, dissident, and activist for disarmament, peace and human rights.
Relevant evidence: Yes