Task: Question Answering
Input (English): Passage: After selecting the music by Alexandrov for the national anthem, Stalin needed new lyrics. He thought that the song was short and, because of the Great Patriotic War, that it needed a statement about the impending defeat of Germany by the Red Army. The poets Sergey Mikhalkov and Gabriel El-Registan were called to Moscow by one of Stalin's staffers, and were told to fix the lyrics to Alexandrov's music. They were instructed to keep the verses the same, but to find a way to change the refrains which described "a Country of Soviets". Because of the difficulty of expressing the concepts of the Great Patriotic War in song, that idea was dropped from the version which El-Registan and Mikhalkov completed overnight. After a few minor changes to emphasize the Russian Motherland, Stalin approved the anthem and had it published on 7 November 1943, including a line about Stalin "inspir[ing] us to keep the faith with the people". The revised anthem was announced to all of the USSR on January 1, 1944 and became official on March 15, 1944.After Stalin's death in 1953, the Soviet government examined his legacy. The government began the de-Stalinization process, which included downplaying the role of Stalin and moving his corpse from Lenin's Mausoleum to the Kremlin Wall Necropolis. In addition, the anthem lyrics composed by Mikhalkov and El-Registan were officially scrapped by the Soviet government in 1956. The anthem was still used by the Soviet government, but without any official lyrics. In private, this anthem became known the "Song Without Words". Mikhalkov wrote a new set of lyrics in 1970, but they were not submitted to the Presidium of the Supreme Soviet until May 27, 1977. The new lyrics, which eliminated any mention of Stalin, were approved on 1 September, and were made official with the printing of the new Soviet Constitution in October 1977. In the credits for the 1977 lyrics, Mikhalkov was mentioned, but references to El-Registan, who died in 1945, were dropped for unknown reasons. 
Question: What was Stalin's revised anthem later known as?
Output (English): "Song Without Words".