The game is HEADS UP (that is, one on one) sit-n-go where our hero wins 60% of his matches and loses 40% of his matches. This translates into an ROI of 9% per match given that the buy-in is 10+1 or 20+2 or 50+5. What is the smallest number of buy-ins that hero must have in his bankroll so that he will have a risk of ruin of ZERO?