There is a temple with 50 entrances. Each entrance has an idol and an priest. I buy some lemons and visit the temple. I give half of all the lemons i had to the first priest. He gives me 1 lemon back as a prasad. Now i visit the second priest. I give half of all the lemons i have, and he give me 1 back. Like this i visit all the idols. At the end i have the same number of lemons.
How many lemons did i start with?