Three from Buttermilk Village (1978)

Three from Prostokvashino (, Troye iz Prostokvashino) is a 1978 Soviet animated film based on the children's book Uncle Fyodor, His Dog and His Cat (Дядя Фёдор, Пёс и Кот) by Eduard Uspensky. The film has two sequels, Vacation in Buttermilk Village (Каникулы в Простоквашино) (1980) and Winter in Buttermilk Village (Зима в Простоквашино) (1984).

More at Wikipedia.