It’s common for Russian students to say «Ни пу́ха ни пера́!» to each other before exams. It literally means "Not a bit of down, nor a single feather," and is said when wishing someone good luck. Wishing good luck in reverse is a classic example of Russian superstition: not to jinx a hunt, you wish hunters bad shooting. The traditional response to this is «К чёрту!» (“To hell!”). This Russian idiom could be compared with the standard American wish for good luck “Break a leg!”