The Opytny (Опытный- Experimental) was a unique destroyer built for the Soviet Navy.
 The Soviet designation was Project 45.
 She was commissioned in 1941 and fought in World War II as part of the Baltic Fleet.
 She was indigenously designed in contrast to the Type 7 which was built with Italian assistance and intended as a prototype for future Soviet destroyers.
 She was not a successful ship, with severe problems with her machinery and with stability.
 Her intended armament was substituted for single guns and the turrets were transferred to the Tashkent.
The Kildin-class destroyer was a series of destroyers built for the Soviet Navy in the late 1950s.
 They were a missile armed version of the Kotlin-class destroyer , and the class was named for Kildin Island.
 Four ships were built around the KSShch (КСЩ, SS-N-1) anti-ship missile.
 When this missile became obsolete in the 1960s, three ships were modernised in 1972-1977.
 All ships were decommissioned in the late 1980s early 1990s.
 The Soviet designation was Project 56EM for the prototype ("Bedovyy"), Project 56M for three series ships, and Project 56U for the modernised ships.
The Kola class was the NATO reporting name for a group of frigates built for the Soviet Navy in the 1950s.
 The Soviet designation was "Storozhevoi Korabl" (escort ship) Project 42.
 These ships were analogous to World War II era destroyer escorts or German Elbing-class torpedo boat s.
 The programme consisted of only 8 ships as these vessels were considered to be too expensive for series production and the smaller and cheaper Riga-class frigate was built instead.
 Radars and sonars were fitted.
Neustrashimy (Неустрашимый, Dauntless) was a destroyer built for the Soviet Navy in the early 1950s.
 She was to be the prototype for an extended production run but only one ship was built.
 "Neustrashimy" was considered too big for series production and a modified design, the Kotlin class was chosen for series production instead.
 The Soviet Designation was "Project 41".
 This was the first Soviet ship to be given a NATO reporting name being called the "Tallinn" class.
The "Sovremenny"-class destroyer is the principal anti-surface warship of the Russian Navy ("Sovremenny" translates like "Modern").
 The Soviet designation for the class was Project 956 "Sarych" (Buzzard).
The Modified Kashin class were six ships built and modified based on the Kashin class destroyer for the Soviet Navy between 1973 and 1980.
 Seven more ships were built after that for the Indian Navy.
 The Soviet designation for the Mod Kashin is "Project 61MP".
The Kashin-class destroyers were a group of guided missile destroyers built for the Soviet Navy in the 1960s and early 1970s.
 Their Soviet designation was Project 61.
 s of 2016 , one ship is in service with the Russian Navy, and five modified ships are in service with the Indian Navy as "Rajput"-class destroyer s.
The Udaloy I" class are a series of anti-submarine destroyers built for the Soviet Navy, eight of which are currently in service with the Russian Navy.
 The Russian designation is "Project 1155 Fregat".
 Twelve ships were built between 1980 and 1991, while a thirteenth ship built to a modified design as the Udaloy II" class followed in 1999.
 They complement the Sovremennyy-class destroyer in anti-aircraft warfare and anti-surface warfare operations.
The "Gnevny" class were a group of destroyers built for the Soviet Navy in the late 1930s – early 1940s.
 They are sometimes known as the "Gremyashchiy"-class destroyer and the Official Soviet Designation was "Project 7".
 These ships fought in World War II.
The Riga class was the NATO reporting name for class of frigates built for the Soviet Navy in the 1950s.
 The Soviet designation for these ships was "Storozhevoi Korabl" (escort ship) "Project 50 Gornostay" ("Ermine stoat").
 The Riga class was analogous to World War II era destroyer escorts.

Question: What was the Soviet designation for the class of destroyer that is complemented by the Udaloy-class destroyer?
Answer: Project 956 "Sarych" (Buzzard)