Question: The Advanced Tactical Fighter (ATF) was a demonstration and validation program undertaken by the United States Air Force, including the Soviet Sukhoi Su-27, a twin-engine supermaneuverable fighter aircraft designed by Sukhoi, it was designed to complement which aircraft?
Sentence (from "Sukhoi Su-27"): It was intended as a direct competitor for the large United States fourth-generation fighters such as the Grumman F-14 Tomcat and F-15 Eagle, with 3530 km range, heavy aircraft ordnance, sophisticated avionics and high maneuverability.
Relevant evidence: No