With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Back to the Future Part II is of a genre.
text_B: Science fiction film -LRB- or sci-fi -RRB- is a genre that uses speculative , fictional science-based depictions of phenomena that are not fully accepted by mainstream science , such as extraterrestrial lifeforms , alien worlds , extrasensory perception and time travel , along with futuristic elements such as spacecraft , robots , cyborgs , interstellar travel or other technologies .. genre. genre. speculative. Speculative fiction. science. science. extraterrestrial lifeforms. Extraterrestrial life in fiction. alien worlds. Planets in science fiction. extrasensory perception. extrasensory perception. time travel. time travel in fiction. spacecraft. List of fictional spacecraft. interstellar travel. interstellar travel. Science fiction films have often been used to focus on political or social issues , and to explore philosophical issues like the human condition .. political. politics. human condition. human condition. In many cases , tropes derived from written science fiction may be used by filmmakers ignorant of or at best indifferent to the standards of scientific plausibility and plot logic to which written science fiction is traditionally held .. science. science. tropes. trope ( literature ). science fiction. science fiction. The genre has existed since the early years of silent cinema , when Georges Melies ' A Trip to the Moon -LRB- 1902 -RRB- employed trick photography effects .. genre. genre. A Trip to the Moon. A Trip to the Moon. trick photography. Special effect. The next major example in the genre was the film Metropolis -LRB- 1927 -RRB- - being the first feature length science fiction movie .. genre. genre. science. science. science fiction. science fiction. Metropolis. Metropolis ( 1927 film ). feature length. feature length. From the 1930s to the 1950s , the genre consisted mainly of low-budget B movies .. genre. genre. After Stanley Kubrick 's landmark 2001  : A Space Odyssey -LRB- 1968 -RRB- , the science fiction film genre was taken more seriously .. genre. genre. science. science. science fiction. science fiction. Stanley Kubrick. Stanley Kubrick. In the late 1970s , big-budget science fiction films filled with special effects became popular with audiences after the success of Star Wars and paved the way for the blockbuster hits of subsequent decades .. science. science. science fiction. science fiction. Star Wars. Star Wars ( film )
related.