  Chances of a gambler are always lower than chances of a casino in the case of
an ideal, mathematically perfect roulette, if the capital of the gambler is
limited and the minimum and maximum allowed bets are limited by the casino.
However, a realistic roulette is not ideal: the probabilities of realisation of
different numbers slightly deviate. Describing this deviation by a statistical
distribution with a width {\delta} we find a critical {\delta} that equalizes
chances of gambler and casino in the case of a simple strategy of the game: the
gambler always puts equal bets to the last N numbers. For up-critical {\delta}
the expected return of the roulette becomes positive. We show that the dramatic
increase of gambler's chances is a manifestation of bunching of numbers in a
non-ideal roulette. We also estimate the critical starting capital needed to
ensure the low risk game for an indefinite time.
