Pyotr Vinogradov, inventor
Senya Kaufman
Kotya Okhotnikov
Valya, music student
Tonya, architecture student
Physical education instructor (uncredited)
Senya's mother (uncredited)
Red army sailor (uncredited)
Young girl (uncredited)
Professor (uncredited)
Spectator at the concert (uncredited)
Middle aged woman (uncredited)
